WO2021061996A1

WO2021061996A1 - Manufacturing system for an energy harvesting thermionic device

Info

Publication number: WO2021061996A1
Application number: PCT/US2020/052507
Authority: WO
Inventors: Joseph Birmingham; James P. BRAINARD
Original assignee: Birmingham Technologies, Inc.
Priority date: 2019-09-25
Filing date: 2020-09-24
Publication date: 2021-04-01
Also published as: WO2021061997A1; WO2021061995A1

Abstract

Embodiments relate to a system for manufacturing energy harvesting thermionic devices, including those of a nano-scale. The system includes a plurality of dispensers to dispense a first material, a second material, and a separation material between the first and second materials. The first material has a first work function value and the second material has a second work function value different from the first work function value. At least one electro spray device is positioned proximal to the third dispenser to deposit a fluid within at least a portion of the separation material. The fluid has particles with a third work function value different from the first and second work function values. The system also includes a guide assembly to transport the first and second electrodes, the positioned separation material, and the fluid to a joint proximal position and form a fabricated product. Related methods are also disclosed.

Description

Manufacturing System for an Energy Harvesting Thermionic Device

BACKGROUND

[0001] Embodiments disclosed herein relate to manufacturing devices directed toward electric power generation, energy conversion, and energy transfer. More specifically, embodiments disclosed herein relate to manufacturing systems for nano-scale energy harvesting devices that generate electric power through thermionic energy conversion and/or thermoelectric energy conversion.

SUMMARY

[0002] The embodiments described herein are directed to a system, and in an embodiment one or more variations of the system and system components, to manufacture energy thermionic harvesting devices, including in exemplary embodiments on a nanometer scale or nano-scale.

[0003] In one aspect, the system is provided with a first dispenser, a second dispenser, and a third dispenser. The first dispenser is configured to dispense a first material having a first work function value. The second dispenser is configured to dispense a second material having a second work function value different from the first work function value. The third dispenser is configured to deposit a separation material between the first and second materials. The system also includes at least one device positioned proximal to the third dispenser and configured to deposit a fluid within at least a portion of the separation material. The fluid has a third work function value different from the first and second work function values. The system further includes a guide assembly operably coupled to the first, second, and third dispensers. The guide assembly is configured to transport the first and second materials, the positioned separation material, and the fluid to a joint proximal position to form a fabricated product.

[0004] In another aspect, the system is provided with a first dispenser and a second dispenser. The first dispenser is configured to dispense a first component. The first component includes a first electrode and a separation material positioned in at least partial communication with the first electrode. The first electrode has a first work function value.

The second dispenser is configured to dispense a second component. The second component includes a second electrode. The second electrode has a second work function value different from the first work function value. The system also includes at least one device positioned proximal to the first dispenser. The device is configured to deposit a fluid within at least a portion of the separation material. At least a portion of the fluid has a third work function value different from the first and second work function values. The system further includes a guide assembly operably coupled to the first and second dispensers. The guide assembly is configured to transport the first and second components to a joint proximal position to form a fabricated product including the first and second components and the fluid.

[0005] In yet another aspect, the system is provided with a first dispenser, a second dispenser, and a third dispenser. The first dispenser is configured to dispense a first material having a first work function value. The second dispenser is configured to dispense a second material having a second work function value different from the first work function value.

The system also includes a first electrospray device and a second electrospray device. The first electrospray device is positioned proximal to the first dispenser. The first electrospray device is configured to deposit at least one first electrospray material over at least a portion of the first material to fabricate a first electrode material having a third work function value. The second electrospray device is positioned proximal to the second dispenser. The second electrospray device is configured to deposit at least one second electrospray material over at least a portion of the second material to fabricate a second electrode material having a fourth work function value. The system further includes a guide assembly operably coupled to the first and second dispensers. The guide assembly is configured to transport the first and second electrode materials to a joint proximal position. The guide assembly is configured to position an opening between the first and second electrode materials. The third dispenser is configured to deposit a separation material into the opening. The system is configured to fabricate a product including the first and second electrode materials and the positioned separation material.

[0006] These and other features and advantages will become apparent from the following detailed description of the exemplary embodiment(s), taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0007] The drawings referenced herein form a part of the specification. Features shown in the drawings are meant as illustrative of only some embodiments, and not of all embodiments, unless otherwise explicitly indicated.

[0008] FIG. 1 depicts a sectional view of an embodiment of a nano-scale energy harvesting thermionic device.

[0009] FIG. 2A depicts a top view of an embodiment of a spacer and adjacent electrodes for use in a nano-scale energy harvesting thermionic device.

[0010] FIG. 2B depicts a top view of an embodiment of a spacer and adjacent electrodes for use in a nano-scale energy harvesting thermionic device.

[0011] FIG. 3 depicts a schematic view of an embodiment of a nano-fluid including a plurality of nanoparticle clusters suspended in a dielectric medium.

[0012] FIG. 4 depicts a schematic view of an embodiment of a manufacturing system for nano-scale energy harvesting thermionic devices.

[0013] FIG. 5 depicts an enlarged schematic view of a portion of the manufacturing system.

[0014] FIG. 6 depicts a schematic perspective view of an arcuate energy harvesting thermionic device.

[0015] FIG. 7 depicts a perspective view of an arcuate energy harvesting thermionic device.

[0016] FIG. 8 depicts a schematic perspective view of a planar energy harvesting thermionic device.

[0017] FIG. 9 depicts a perspective view of a first repository of layered materials that may be used to manufacture the energy harvesting thermionic device(s).

[0018] FIG. 10 depicts a perspective view of a second repository of layered materials that may be used to manufacture the energy harvesting thermionic device(s). [0019] FIG. 11 depicts a flow diagram of an embodiment of a system to manufacture electric power generation modules with the device(s) described herein.

[0020] FIG. 12 depicts a schematic view of an embodiment of a manufacturing system for nano-scale energy harvesting thermionic device(s).

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0021] It will be readily understood that the components of exemplary embodiments, as generally described herein and illustrated in the Figures, may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the apparatus, system, and method of the present embodiments, as presented in the Figures, is not intended to limit the scope of the embodiments, as claimed, but is merely representative of selected embodiments.

[0022] Reference throughout this specification to “a select embodiment,” “one embodiment,” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “a select embodiment,” “in one embodiment,” or “in an embodiment” in various places throughout this specification are not necessarily referring to the same embodiment. The embodiments described herein, including individual or multiple features, components, attributes, steps, etc. of the embodiments, may be combined with one another in various combinations and modifications.

[0023] The illustrated embodiments will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the embodiments as claimed herein.

[0024] Thermoelectric power conversion presents an avenue to harvest and convert thermal energy into electricity. Thermoelectric power generation may involve forming a junction between a first electrode and a different second electrode, where the two electrodes experience a temperature gradient. Based on the Seebeck effect, the temperature gradient induces a voltage. Higher temperature differentials tend to produce higher voltages and electric currents. However, due to the transfer of heat between the two materials at the junction, a thermal backflow is introduced which reduces the efficiency of thermoelectric power conversion systems.

[0025] Thermionic power conversion also presents an avenue to convert thermal energy into electrical energy. Thermoelectric power conversion generators convert thermal energy to electrical energy by emission of electrons from a heated emitter electrode ( i.e ., a cathode). Electrons flow from an emitter electrode, across an inter-electrode gap, to a collector electrode {i.e., an anode), through an external load, and return back to the emitter electrode, thereby converting heat to electrical energy. Recent improvements in thermionic power converters pertain to material selection based on work functions and corresponding work function values for the electrodes and using a fluid to fill the inter-electrode gap. Electron transfer density is limited by the materials of the electrodes and the materials of the fluid in the inter-electrode gap {i.e., the associated work functions). Representative and exemplary materials, features, conditions, etc. associated with thermal energy harvesting thermionic devices are described in further detail below.

[0026] To provide additional details for an improved understanding of selected embodiments of the present disclosure that combine the use of thermoelectric and thermionic power conversion, reference is now made FIG. 1 illustrating a sectional view of an embodiment of an energy harvesting thermionic device (100) that is configured to convert thermal energy (or heat) into electrical power, e.g., electricity. In exemplary embodiments, the device (100) may be nano-scale and/or contain one or more nano-scale components. Each of the dimensions, including a thickness dimension defined parallel to a first-axis, also referred to herein as a vertical axis, i.e., the Y-axis in FIG. 1, a longitudinal dimension parallel to a second-axis, i.e., the X-axis in FIG. 1, also referred to herein as a horizontal axis, and a lateral dimension parallel to a third axis-axis, i.e., the Z-axis in FIG. 1, orthogonal to the first-axis and second axis, are shown for reference. The X-axis, Y-axis, and Z-axis are orthogonal to each other in physical space.

[0027] The nano-scale energy harvesting thermionic device (100) is sometimes referred to herein as a cell. In an embodiment, the energy harvesting thermionic device (100) is illustrated as a sheet or a plurality of adjacently positioned sheets or layers, e.g., that may be stacked or wound. A plurality of devices (100) may be organized as a plurality of cells, or in an embodiment a plurality of layers, with the cells or layers arranged in series or parallel, or a combination of both to generate electrical power at the desired voltage, current, and power output.

[0028] The energy harvesting thermionic device (100) includes an emitter electrode (also referred to herein as a cathode) (102) and a collector electrode (also referred to herein as an anode) (104) positioned to define an inter-electrode gap (or interstitial space) therebetween. In an embodiment, a spacer (106) of separation material, sometimes referred to herein as a standoff or spacer, maintains separation between the electrodes (102) and (104). While the spacer (106) is referred to herein in the singular, it should be understood that the spacer (106) may comprise a plurality of components. In an embodiment, the spacer (106) is an insulator or comprises one or more materials that collectively exhibit electrically non-conductive properties. The spacer (106) is in direct contact with the electrodes (102) and (104). The electrodes (102) and (104) and the spacer (106) define a plurality of apertures (108), also referred to herein as cavities (discussed further below with respect to FIGS. 2A and 2B), in the inter-electrode gap. The apertures (108) extend in the Y direction between the electrodes (102) and (104) for a distance (110) in the range of, for example, about 1 nanometer (nm) to about 100 nm, and in an embodiment, the distance (110) is in a range of about 1 nm to about 20 nm. A fluid (112), also referred to herein as a nano-fluid (discussed further herein with reference to FIG. 3), is received and maintained within one or more, and preferably each, of the apertures (108).

[0029] In another embodiment, no spacer (106) is used and only the nano-fluid (112) is positioned between the electrodes (102) and (104). Accordingly, the energy harvesting thermionic device (100) includes two opposing electrodes (102) and (104), optionally separated the spacer (106), with a plurality of apertures (108) extending between the electrodes (102) and (104) and configured to receive the nano-fluid (112).

[0030] The emitter electrode (102) and the collector electrode (104) each may be fabricated with different materials, with the different materials having separate and different work function values. As used herein, the work function of a material, or in an embodiment a combination of materials, is the minimum thermodynamic work, i.e., minimum energy, needed to remove an electron from a solid to a point in a vacuum immediately outside a solid surface of the material. The work function is a material-dependent characteristic. Work function values are typically expressed in units of electron volts (eV). Accordingly, the work function of a material determines the minimum energy required for electrons to escape the surface, with lower work functions generally facilitating electron emission.

[0031] The difference in work function values between the electrodes (102) and (104) due to the different electrode materials influences the voltage that can be achieved. Thus, to generate high power, the difference in work function values between the electrodes (102) and (104) is significant in an exemplary embodiment. In an embodiment, the emitter electrode (102) has a higher work function value than the collector electrode (104). The difference in work function values between the electrodes (102) and (104) due to the different electrode materials induces a contact potential difference between the electrodes (102) and (104) that has to be overcome, e.g., by the application of heat to the emitter electrode (102), to transmit electrons through the fluid (112) within the apertures (108) from the emitter electrode (102) to the collector electrode (104). Both electrodes (102) and (104) emit electrons; however, as explained in more detail elsewhere herein, once the contact potential difference is overcome, the emitter electrode (102) will emit significantly more electrons than the collector electrode (104). The total of the work function value of the collector electrode (104) and the contact potential difference is less than or equal to the work function of the emitter electrode (102) in an exemplary embodiment. Maximum flow occurs when the total of the work function value of the collector electrode (104) and the contact potential equals the work function of the emitter electrode (102).

[0032] Both electrodes (102) and (104) emit electrons; however, once the contact potential difference is overcome, the emitter electrode (102) will emit significantly more electrons than the collector electrode (104), which is influenced by an electric field that suppresses electron production from the collector electrode (104). A net flow of electrons is transferred from the emitter electrode (102) to the collector electrode (104) through the apertures (108). This net electron current (114) causes the emitter electrode (102) to become positively charged and the collector electrode (104) to become negatively charged. Accordingly, the energy harvesting device (100) generates an electron flow (114) that is transmitted from the emitter electrode (102) to the collector electrode (104).

[0033] The emitter electrode (102) is manufactured with a first backing (116), which may comprise, for example, a polyester film, e.g., Mylar^®, and a first layer (118) extending over the first backing (116). The first layer (118) may be comprised of, for example, graphene, platinum (Pt), or other suitable materials. The emitter electrode (102) has an emitter electrode measurement (120) that in an embodiment is approximately 0.25 millimeters (mm), such value being non-limiting, and in an embodiment may have a measurement of, for example, about 2 nm to about 0.25 mm, such values being non-limiting. The first backing (116) is shown in FIG. 1 with a first backing measurement (122), and the first layer (118) is shown in FIG. 1 with a first layer measurement (124), extending in the Y direction. In an embodiment, the first backing measurement (122) and the first layer measurement (124) are in a range of, for example, about 0.01 mm to about 0.125 mm, and in an embodiment are each approximately 0.125 mm, such values being non-limiting. In an embodiment, the first backing measurement (122) and the first layer measurement (124) may have the same or different measurement values.

[0034] In an embodiment, the first layer (118) is sprayed onto the first backing (116) so as to embody the first layer (118) as a nanoparticle layer that is approximately 2 nm ( ._<?., the approximate length or diameter of a nanoparticle), where the 2 nm value should be considered non-limiting. In an embodiment, the thickness (124) of the first layer (118) may be in a range of, for example, about 1 nm to about 20 nm, or about 2 nm to about 20 nm. In another embodiment, the thickness (124) of the first layer (118) may be in a range of, for example, 0.01 mm to 0.125 mm. Generally, smaller thicknesses have higher energy densities and less wasted energy. The first backing (116) has an outer surface (128). The first backing (116) and the first layer (or the nanoparticle layer) (118) define a first interface (130) therebetween. The first layer (or the nanoparticle layer (118)) defines a first surface (132) facing the inter-electrode gap. Alternatively to spraying, the first layer (118) may be pre formed and applied to the first backing layer (116), or vice versa, i.e., the first backing layer (116) applied to the first layer (118).

[0035] A first coating (134), which in an embodiment is comprised of cesium oxide (CS2O) and discussed further herein, at least partially covers the first surface (132) to form an emitter surface (136) of the emitter electrode (102) that directly interfaces with a first spacer surface (138). Accordingly, the emitter electrode (102) of the embodiment is manufactured with a first layer (or nanoparticle layer) (118) interposed between the first backing (116) and the first coating (134).

[0036] The collector electrode (104) includes a second backing (146), which in an embodiment is comprised of, for example, a polyester film, and at least one second layer

(148), which in an embodiment is comprised of, for example, graphene or aluminum (Al), extending over the second backing (146). The collector electrode has a collector electrode measurement (150) extending in the Y direction that in an embodiment is approximately 0.25 millimeters (mm), such values being non-limiting, and in an embodiment may have a measurement of, for example, about 2 nm to about 0.25 mm, such values being non-limiting. For example, in an embodiment, a second backing measurement (152) of the second backing (146) and a second layer measurement (154) of the second layer (148) are each approximately 0.125 mm, such values being non-limiting. In an embodiment, the second backing measurement (152) and the second layer measurement (154) may be in a range of, for example, about 0.01 mm to about 0.125 mm, and in an embodiment are each approximately 0.125 mm, such values being non-limiting. The second backing measurement (152) and the second layer measurement (154) may have the same or different measurement values.

[0037] In an embodiment, the second layer (148) is sprayed onto the second backing (146) to embody the second layer (148) as a nanoparticle layer that is approximately 2 nm, where the 2 nm value should be considered non-limiting. In an embodiment, the second layer measurement (154) of the second layer (148) may be in a range of, for example, about 1 nm to about 20 nm, or about 2 nm to about 20 nm. In another embodiment, the second layer measurement (154) of the second layer (148) may be in a range of, for example, 0.01 mm to 0.125 mm. As discussed above in connection with the first layer (118), generally, smaller thicknesses have higher energy densities and less wasted energy. The second backing (146) has an outer surface (158). The second backing (146) and the second layer/nanoparticle layer (148) define a second interface (160). The second layer (or the second nanoparticle layer) (148) defines a second surface (162) facing the inter-electrode gap. Alternatively to spraying, the second layer (148) may be pre-formed and applied to the second backing (146) or vice versa, i.e., the second backing (146) applied to the second layer (148).

[0038] A second coating (164), which in an embodiment is comprised of cesium oxide (CS O) and discussed further herein, at least partially covers the second surface (162) to form a collector surface (166) that directly interfaces with a second surface (168) of the spacer (106). Accordingly, in an embodiment the collector electrode (104) is manufactured with the second layer/nanoparticle layer (148) on the second backing (146) and a CS O coating (164) on the second surface (162). [0039] In an exemplary embodiment, the first and second coatings, (134) and (164), respectively, are formed on the first and second surfaces (132) and (162), respectively. In an embodiment, an electrospray or nano-fabrication techniques, with one or more predetermined patterns, is employed to form or apply the first and second coatings, (134) and (164), respectively. The first and second coatings (134) and (164) can be applied in one or more predetermined patterns that may be the same as or different from one another.

[0040] In exemplary embodiments, the first surface (132) is a platinum surface and the second surface (162) is an aluminum surface. In an embodiment, a percentage of coverage of each of the first surface (132) and second surface (162) with the respective CS O coating layers (134) and (164) is within a range of at least 50%, and up to 70%, and in at least one embodiment is about 60%. The CS O coatings (134) and (164) reduce the work function values of the electrodes (102) and (104) from the work function values of platinum (Pt), which in an embodiment is 5.65 electron volts (eV), and aluminum, which in an embodiment is 4.28 eV. In an embodiment, the emitter electrode (102) with the CS O coating layer (134) has a work function value ranging from about 0.5 to about 2.0 eV, and in an embodiment is approximately 1.5 eV, and the collector electrode (104) with the CS O coating layer (164) has a work function value of about 0.5 to about 2.0 eV, and in an embodiment is approximately 1.5 eV.

[0041] In an embodiment, the electrodes (102) and (104) are comprised of graphene, and are referred to herein as graphene electrodes (102) and (104). The graphene electrodes (102) and (104) can exhibit work function values below 1.0 eV when coated with cesium oxide, gold, tungsten, and other elements and compounds. Sulfur may be incorporated into the coatings (134) and (164) to improve the bonding of the coatings (134) and (164) to the graphene electrodes (102) and (104), respectively, particularly where the first and second layers (118) and (148) of the electrodes (102) and (104) comprise graphene and the sulfur creates covalent bonding between the electrodes (102) and (104) and their respective coatings (134) and (164). The respective work function values of the electrodes (102) and (104) can be made to differ, even when both are comprised of graphene, for example by incorporating different coatings (134) and (164) onto the electrodes (102) and (104). Suitable graphene electrodes are available through ACS (Advanced Chemical Suppliers) Materials, and include Trivial Transfer Graphene™ (TTG 10055). [0042] In an embodiment, the surface area coverage on the emitter electrode (102) or the collector electrode (104) of CS O is spatially resolved, e.g. applied in a pattern or non- uniform across the length of the corresponding surface, and provides a reduction in a corresponding work function to a minimum value. In an embodiment, the work function value, from a maximum of about 2.0 eV is reduced approximately 60-80% corresponding to the surface coverage of the CS O, e.g. cesium oxide. Accordingly, the work function values of the electrodes (102) and (104) are essential to the operation of the energy harvesting thermionic device (100) as described herein.

[0043] Platinum (Pt)-coated on copper foil and aluminum (Al) materials optionally are selected for the electrodes (102) and (104), respectively, due to at least some of their metallic properties, e.g., strength and resistance to corrosion, and the measured change in work function when the thermionic emissive material of CS O or other materials disclosed herein is layered thereon. Alternative materials may be used, such as graphene, noble metals including, and without limitation, rhenium (Re), osmium (Os), ruthenium (Ru), iridium (Ir), rhodium (Rh), and palladium (Pd), or any combination of these metals. In addition, and without limitation, non-noble metals such as gold (Au), tungsten (W), tantalum (Ta), and molybdenum (Mo), and any combination thereof, may also be used. For example, and without limitation, tungsten (W) nanoparticles may be used rather than Pt nanoparticles to form surface (132), and Au nanoparticles may be used rather than Al nanoparticles to form surface (162). Accordingly, the selection of the materials to use to form the nanoparticle surfaces (132) and (162) is principally based on the work functions of the electrodes (102) and (104), and more specifically, the difference in the work functions once the electrodes (102) and (104) are fully fabricated.

[0044] The selection of the first and second coatings (134) and (164), respectively, e.g., thermionic electron emissive material, to deposit on the first surface (132) and the second surface (162), respectively, is partially based on the desired work function value of the electrodes (102) and (104), respectively, and chemical compatibility between the deposited materials, and the deposited thermionic electron emissive materials (134) and (164). Deposition materials include, but are not limited to, thorium, aluminum, cerium, and scandium, as well as oxides of alkali or alkaline earth metals, such as cesium, barium, calcium, and strontium, as well as combinations thereof and combinations with other materials. In at least one embodiment, the thickness of the layer of patterned thermionic electron emissive material of the first and second coatings (134) and (164), respectively, is approximately 2 nm, where the 2 nm value should be considered non-limiting. Accordingly, the electrodes (102) and (104) have the desired work functions.

[0045] FIG. 2A depicts a top view of an embodiment of a spacer (200) and the adjacent electrodes (262) and (264) for use in the nano-scale energy device, such as the device (100) having electrodes (102) and (104) as shown and described in FIG. 1. The spacer (200) and electrodes (262) and (264) are not shown to scale.

[0046] Electrodes (262) and (264) are shown in broken lines. The spacer (200), as shown and described herein, includes a plurality of interconnected edges (202). The edges (202) have a thickness or edge measurement (204) in the range of about 2.0 nm to about 0.25 mm. As shown herein, the edges (202) are interconnected. In an embodiment, the interconnected edges (202) collectively define a plurality of hexagonal apertures, also referred to herein as cavities (206), in a honeycomb array (208). The cavities (206) extend in the Y direction. In an embodiment, the spacer (200) may be configured as a uniform or relatively uniform layer, e.g., contiguous and with or without limited apertures. The apertures or cavities, either uniformly or non-uniformly provided across the width and/or length of the spacer material, may be in a range of, for example, greater than 0 mm (e.g., 2 nm) to about 0.25 mm in the Y- axis direction, similar to an embodiment of the spacer (106) of FIG. 1.

[0047] Referring to FIG. 2B, a top view of an embodiment of a spacer (270) and the adjacent electrodes (262) and (264) is shown for use in the energy harvesting thermionic device, such as the device (100) with the electrodes (102) and (104) as shown and described in FIG. 1. The embodiment shown and described in FIG. 2B is provided with similar numbers as that shown in FIG. 2A, where appropriate, to designate identical or like parts. The spacer (270) may be comprised of a permeable or semi-permeable material, which in an embodiment may be adapted to receive or be coated or impregnated with the nanofluid.

[0048] Referring to FIG. 2A, in an embodiment, the apertures (206) have a first dimension (210) and a second dimension (212) each having a value in a range between, for example, 2.0 nm and 100 microns. In an embodiment, the edges (202), the apertures (206), and the array (208) may form various shapes, configurations, and sizes, including the dimensions and sizing of the apertures (206), that enable operation of spacer (200) as described herein, including, without limitation, circular, rectangular, and elliptical apertures (206).

[0049] The spacers (200) and (270), shown in FIGS. 2A and 2B, respectively, also include first and second edges (214) and (216), respectively, that define the dimensions, e.g. outer edges, of the spacer (200). The spacer (200), (270) has a distance measure (218) in the lateral dimension (Z) between the lateral side edges (214) and (216). In an embodiment, the distance measure (218) has a range between about 1 nm to approximately 10 microns.

[0050] As shown in FIGS. 2A and 2B, the electrodes (262) and (264) are offset in the lateral dimension Z with respect to one another and with respect to the spacer (200), (270). Specifically, the emitter electrode (262) includes opposite first and second lateral side edges (230) and (232) separated by a first distance (234). The collector electrode (264) includes opposite third and fourth lateral side edges (240) and (242) separated by a second distance (244). The values of the first and second distances (234) and (244) may be the same or different from one another, and may be within a range of, for example, approximately 10 mm to approximately 2.0 m.

[0051] With respect to the first electrode (262), the first lateral side edge (230) extends in the lateral direction Z beyond the first lateral support side edge (214) of the spacer (200), (270) by a third distance (236), and the second lateral support side edge (216) of the spacer (200), (270) extends in the lateral direction Z beyond the second lateral side edge (232) by a fourth distance (228).

[0052] With respect to the second electrode (264), the first lateral support side edge (214) of the spacer (200), (270) extends in the lateral direction Z beyond the third lateral side edge (240) by a fifth distance (226), and the fourth lateral side edge (242) extends in the lateral direction Z beyond the second lateral support side edge (216) of the spacer (200), (270) by a sixth distance (248).

[0053] In embodiments, the third distance (236), the fourth distance (228), the fifth distance (226), and the sixth distance (248) may be the same or different from one another and within a range of, for example, approximately 1.1 nm to approximately 10 microns. The spacer (200), (270) may have a lateral measurement (218) with respect to the Z-axis greater than lateral measurements (234) and (244) of the electrodes (262) and (264), respectively. The spacer design and measurements shown and described herein reduce a potential for electrodes, such as the electrodes (102) and (104), to contact one another when the spacer (200), (270) is incorporated into the device (100) of FIG. 1. The direct contacting of the electrodes (102) and (104) would create a short circuit.

[0054] Each of the lateral support side edges (214) and (216) may receive at least one layer of an electrically insulating sealant that electrically isolates the portions (250) and (252) of the electrodes (262) and (264), respectively, that extend beyond the lateral support side edges (214) and (216), respectively. Further, as described above, each of the electrodes (262) and (264) may be offset from the spacer (200), (270) to, along with the sealant, reduce the potential for the electrodes (262) and (264) contacting each other and creating a short circuit.

[0055] In exemplary embodiments, the at least one spacer (200) and/or (270), which in exemplary embodiments are dielectric spacers, as shown and described in FIGS. 2A and 2B, respectively, is fabricated with a dielectric material, such as, and without limitation, silica (silicon dioxide), alumina (aluminum oxide), titania (titanium dioxide), and boron-nitride.

The apertures (206) extend between the electrodes (262) and 264) for the distance (110), e.g., in the Y-dimension, in a range from about 1 nanometer (nm) to about 10 microns. A fluid, e.g., the nano-fluid (112), as shown and described in detail in FIG. 3, is received and maintained within each of the apertures (206). The dielectric spacer (200), (270) is positioned between, and in direct contact with, the electrodes (262) and (264).

[0056] Referring to FIG. 3, a diagram (300) is provided to illustrate a schematic view of an embodiment of a fluid or medium (302), also referred to herein as a nano-fluid. As shown, the nano-fluid (302) includes a plurality of gold (Au) nanoparticle clusters (304) and a plurality of silver (Ag) nanoparticle clusters (306) suspended in a dielectric medium (308). In some embodiments, and without limitation, the dielectric medium (308) is selected from one of the groups including alcohols, ketones (e.g., acetone), ethers, glycols, olefins, and alkanes

( i.e ., those alkanes with greater than three carbon atoms, e.g., tetradecane). In FIG. 3, each cluster (306) and (308) is embodied as a single nanoparticle, in particular a single Au nanoparticle or a single Ag nanoparticle, with a dielectric coating (discussed below). In some embodiments, and without limitation, the dielectric medium (308) is an alcohol, a ketone

(e.g., acetone), an ether, a glycol, an olefin, and/or an alkane (e.g., those alkanes with greater than three carbon atoms, e.g., tetradecane). In an embodiment, the dielectric medium (308) is water or silicone oil. Alternatively, in at least one embodiment, the dielectric medium (308) is a sol-gel with aerogel-like properties and low thermal conductivity values that reduce heat transfer therethrough, e.g., thermal conductivity values as low as 0.013 watts per meter- degrees Kelvin (W/m-K) as compared to the thermal conductivity of water at 20 degrees Celsius (°C) of 0.6 W/m-K. Appropriate materials are selected to fabricate the nanoparticle clusters (304) and (306). The materials selected for the nanoparticle clusters (304) and (306) may have work function values that are greater than the work function values for associated electrodes, such as the electrodes (102) and (104) in FIG. 1. For example, the work function values of the Au nanoparticle clusters (304) and the Ag nanoparticle clusters (306) are about 4.1 eV and 3.8 eV, respectively.

[0057] At least one layer of a dielectric coating (310), such as a monolayer of alkanethiol material, is deposited on the Au and Ag nanoparticle clusters (304) and (306), respectively, to form a dielectric barrier thereon. In an embodiment, the deposit of the dielectric coating (310) is performed via electrospray. The alkanethiol material includes, but is not limited to dodecanethiol and/or decanethiol. Additionally or alternatively, the dielectric coating (310) may be a halogenoalkane or alkyl halide, in which one or more of the hydrogen atoms of the alkane are replaced by halogen atom(s), i.e., fluorine, chlorine, bromine, or iodine. The deposit of the dielectric coating (310), such as alkanethiol, reduces coalescence of the nanoparticle clusters (304) and (306). In at least one embodiment, the nanoparticle clusters (304) and (306) have a diameter in the range of about 1 nm to about 3 nm. In an embodiment, the nanoparticle clusters (304) and (306) have a diameter of about 2 nm. The nanoparticle clusters of Au (304) and Ag (306) are tailored to be electrically conductive with charge storage features (i.e., capacitive features), minimize heat transfer through the spacer apertures (206) of FIG. 2A, with low thermal conductivity values, minimize ohmic heating, eliminate space charges in the spacer apertures (206), and prevent arcing. The plurality of Au and Ag nanoparticle clusters (304) and (306), respectively, are suspended in the dielectric medium (308). The nano-fluid (302), including the suspended nanoparticle clusters (304) and (306), provides a conductive pathway for electrons to travel across the spacer apertures (206) from, for example with reference to FIG. 1, the emitter electrode (102) to the collector electrode (104) through charge transfer. Accordingly, in at least one embodiment, a plurality of Au and Ag nanoparticle clusters (304) and (306) are mixed together in a dielectric medium (308) to form a nano-fluid (302), the nano-fluid (302) residing in the apertures (108) of FIG. 1 and/or apertures (206) of FIG. 2A and/or the permeable or semi-permeable material of FIG. 2B. [0058] The Au nanoparticle clusters (304) according to exemplary embodiments are dodecanethiol functionalized gold nanoparticles. In exemplary embodiments, the Au nanoparticle clusters (304) have an average particle size of about 1 nm to about 3 nm, at about 2% (weight/volume (grams/ml)). According to exemplary embodiments, the Ag nanoparticle clusters (306) are dodecanethiol functionalized silver nanoparticles. In some embodiments, the Ag nanoparticle clusters (306) have an average particle size of about 1 nm to about 3 nm, at about 0.25% (weight/volume percent). In an embodiment, the average particle size of both the Au and Ag nanoparticle clusters (304) and (306) is at or about 2 nm. The Au and Ag cores of the nanoparticle clusters (304) and (306) are selected for their abilities to store and transfer electrons. In an embodiment, a 50%-50% mixture of Au and Ag nanoparticle clusters (304) and (306) are used. However, a mixture in the range of 1-99% Au- to-Ag could be used as well. Electron transfers are more likely to occur between nanoparticle clusters (304) and (306) with different work functions. In an exemplary embodiment, a mixture of nearly equal (molar) numbers of two different nanoparticle clusters (304) and (306), e.g., Au and Ag, provides good electron transfer. Accordingly, nanoparticle clusters are selected based on particle size, particle material (with the associated work function values), mixture ratio, and/or electron affinity.

[0059] Conductivity of the nano-fluid (302) can be increased by increasing concentration of the nanoparticle clusters (304) and (306). The nanoparticle clusters (304) and (306) may have a concentration within the nano-fluid (302) of, for example, about 0.1 mole/liter to about 2 moles/liter. In at least one embodiment, the Au and Ag nanoparticle clusters (304) and (306) each have a concentration of at least 1 mole/liter. In at least one embodiment, a plurality of Au and Ag nanoparticle clusters (304) and (306) are mixed together in a dielectric medium (308) to form a nano-fluid (302), the nano-fluid (302) residing in, for example, the apertures (108) of FIG. 1, the apertures (206) of FIG. 2A, and/or the permeable or semi- permeable material of FIG. 2B.

[0060] The stability and reactivity of colloidal particles, such as Au and Ag nanoparticle clusters (304) and (306), are determined largely by a ligand shell formed by the alkanethiol coating (310) adsorbed or covalently bound to the surface of the nanoparticle clusters (304) and (306). The nanoparticle clusters (304) and (306) tend to aggregate and precipitate, which can be prevented by the presence of a ligand shell of the non-aggregating polymer alkanethiol coating (310) enabling these nanoparticle clusters (304) and (306) to remain suspended. Adsorbed or covalently attached ligands can act as stabilizers against agglomeration and can be used to impart chemical functionality to the nanoparticle clusters (304) and (306). Over time, the surfactant nature of the ligand coatings is overcome and the lower energy state of agglomerated nanoparticle clusters is formed. Over time, agglomeration may occur due to the lower energy condition of nanoparticle cluster accumulation and occasional addition of a surfactant may be used. Examples of surfactants include, without limitation, Tween^® 20 and Tween^® 21.

[0061] In the case of the nano-fluid (302) of FIG. 3 substituted for the nano-fluid (112) of FIG. 1, electron transfer through collisions of the plurality of nanoparticle clusters (304) and (306) is illustrated. The work function values of the nanoparticle clusters (304) and (306) are much greater than the work function values of the emitter electrode (102) (e.g., about 0.5 eV to about 2.0 eV) and the collector electrode (104) (e.g., about 0.5 eV to about 2.0 eV). The nanoparticle clusters (304) and (306) are tailored to be electrically conductive with capacitive ( i.e ., charge storage) features while minimizing heat transfer therethrough. Accordingly, the suspended nanoparticle clusters (304) and (306) provide a conductive pathway for electrons to travel across the apertures (108) from the emitter electrode (102) to the collector electrode (104) through charge transfer.

[0062] Thermally-induced Brownian motion causes the nanoparticle clusters (304) and (306) to move within the dielectric medium (308), and during this movement the nanoparticle clusters (304) and (306) occasionally collide with each other and with the electrodes (102) and (104). As the nanoparticle clusters (304) and (306) move and collide within the dielectric medium (308), the nanoparticle clusters (304) and (306) chemically and physically transfer charge. The nanoparticle clusters (304) and (306) transfer charge chemically when electrons (312) hop from the electrodes (102) and (104) of FIG. 1 to the nanoparticle clusters (304) and (306) and from one nanoparticle cluster (304) and (306) to another nanoparticle cluster. The hops primarily occur during collisions. Due to the electric field affecting the collector electrode (104), electrons (312) are more likely to move from the emitter electrode (102) to the collector electrode (104) via the nanoparticle clusters (304) and (306) rather than in the reverse direction. Accordingly, a net electron current from the emitter electrode (102) to the collector electrode (104) via the nanoparticle clusters (304) and (306) is the primary and dominant current of the nano-scale energy harvesting device (100). [0063] The nanoparticle clusters (304) and (306) transfer charge physically ( i.e ., undergo transient charging) due to the ionization of the nanoparticle clusters (304) and (306) upon receipt of an electron, and the electric field generated by the differently charged electrodes (102) and (104). The nanoparticle clusters (304) and (306) become ionized in collisions when the clusters gain or lose an electron (312). Positive and negative charged nanoparticle clusters (304) and (306) in the nano-fluid (302) migrate to the negatively charged collector electrode (104) and the positively charged emitter electrode (102), respectively, providing an electrical current flow. This ion current flow is in the opposite direction from the electron current flow, but less in magnitude than the electron flow.

[0064] Some ion recombination in the nano-fluid (302) may occur, which diminishes both the electron and ion current flow. Electrode separation may be selected at an optimum width (or thickness in the Y direction in FIG. 1) to maximize ion formation and minimize ion recombination. In an exemplary embodiment, the electrode separation (110) is less than about 10 nm to support maximization of ion formation and minimization of ion recombination. In an embodiment, the nanoparticle clusters (304) and (306) have a maximum dimension of, for example, about 2 nm. The electrode separation distance (110) as defined by the spacer (106) (or the spacer (200) or the permeable/semi-permeable material (270) of FIGS. 2A and 2B, respectively) has an upper limit of, for example, about 1000 nm, preferably about 100 nm, and more preferably about 20 nm, and the electrode separation distance (110) of 20 nm is equivalent to approximately 10 nanoparticle clusters (304) and (306). Therefore, the electrode separation distance (110) of about 20 nm provides sufficient space within the apertures (108) for nanoparticle clusters (304) and (306) to move around and collide, while minimizing ion recombination. For example, in an embodiment, an electron can hop from the emitter electrode (102) to a first set of nanoparticle clusters (304) and (306) and then to a second, third, fourth, or fifth set of nanoparticle clusters (304) and (306) before hopping to the collector electrode (104). A reduced quantity of hops mitigates ion recombination opportunities. Accordingly, ion recombination in the nano-fluid (302) is minimized through an electrode separation distance (110) selected at an optimum width to maximize ion formation and minimize ion recombination.

[0065] In an exemplary embodiment, when the emitter electrode (102) and the collector electrode (104) are initially brought into close proximity, the electrons of the collector electrode (104) have a higher Fermi level than the electrons of the emitter electrode (102) due to the lower work function of the collector electrode (104). The difference in Fermi levels drives a net electron current that transfers electrons from the collector electrode (104) to the emitter electrode (102) until the Fermi levels are equal, i.e., the electrochemical potentials are balanced and thermodynamic equilibrium is achieved. The transfer of electrons between the emitter electrode (102) and the collector electrode (104) results in a difference in charge between the emitter electrode (102) and the collector electrode (104). This charge difference sets up the voltage of the contact potential difference and an electric field between the emitter electrode (102) and the collector electrode (104), where the polarity of the contact potential difference is determined by the material having the greatest work function. With the Fermi levels equalized, no net current will flow between the emitter electrode (102) and the collector electrode (104). Accordingly, electrically coupling the emitter electrode (102) and the collector electrode (104) with no external load results in attaining the contact potential difference between the electrodes (102) and (104) and no net current flow between the electrodes (102) and (104) due to attainment of thermodynamic equilibrium between the two electrodes (102) and (104).

[0066] The energy harvesting thermionic device (100) can generate electric power with or without additional heat input ( e.g ., at room temperature). Heat added to the emitter electrode (102) will raise the temperature of the emitter electrode (102) and the Fermi level of the emitter electrode (102) electrons. With the Fermi level of the emitter electrode (102) higher than the Fermi level of the collector electrode (104), a net electron current will flow from the emitter electrode (102) to the collector electrode (104) through the nano-fluid (112), (302). If the device (100) is placed into an external circuit, such that the external circuit is connected to the electrodes (102) and (104), the same amount of electron current will flow through the external circuit from the collector electrode (104) to the emitter electrode (102). Heat energy added to the emitter electrode (102) is carried by the electrons (312) to the collector electrode (102). The bulk of the added energy is transferred to the external circuit for conversion to useful work, some of the added energy is transferred through collisions of the nanoparticle clusters (304) and (306) with the collector electrode (104), and some of the added energy is lost to ambient as waste energy. As the energy input to the emitter electrode (102) increases, the temperature of the emitter electrode (102) increases, and the electron transmission from the emitter electrode (102) increases, thereby generating more electron current. As the emitter electrode (102) releases electrons onto the nanoparticle clusters (304) and (306), energy is stored in the energy harvesting thermionic device (100). Accordingly, the energy harvesting thermionic device (100) generates, stores, and transfers charge and moves heat energy associated with a temperature difference, where added energy causes the production of electrons to increase from the emitter electrode (102) into the nano-fluid (112), (302).

[0067] The nano-fluid (302) can be substituted into the device (100) of FIG. 1 and used to transfer charges from the emitter electrode (102) to one of the mobile nanoparticle clusters (304) and (306) via intermediate contact potential differences from the collisions of the nanoparticle clusters (304) and (306) with the emitter electrode (102) induced by Brownian motion of the nanoparticle clusters (304) and (306). Selection of dissimilar nanoparticle clusters (304) and (306) that include Au nanoparticle clusters (304) and Ag nanoparticle clusters (306), which have greater work function values of about 4.1 eV and about 3.8 eV, respectively, than the work functions of the electrodes (102) and (104), improves transfer of electrons to the nanoparticle clusters (304) and (306) from the emitter electrode (102) to the collector electrode (104). This relationship of the work function values of the Au and Ag nanoparticle clusters (304) and (306) improves the transfer of electrons to the nanoparticle clusters (304) and (306) through Brownian motion and electron hopping. Accordingly, the selection of materials within the energy harvesting thermionic device (100) improves electric current generation and transfer therein through enhancing the release of electrons from the emitter electrode (102) and the conduction of the released electrons across the nano-fluid (112), (302) to the collector electrode (104).

[0068] As the electrons (312) hop from nanoparticle cluster (304) and (306) to nanoparticle cluster (306) and (304), single electron charging effects that include the additional work required to hop an electron (312) onto a nanoparticle cluster (304) and (306) if an electron (312) is already present on the nanoparticle cluster (304) and (306), determine if hopping additional electrons (312) onto that particular nanoparticle cluster (304) and (306) is possible. Specifically, the nanoparticle clusters (304) and (306) include a voltage feedback mechanism that prevents the hopping of more than a predetermined number of electrons to the nanoparticle cluster (304) and (306). This prevents more than the allowed number of electrons (312) from residing on the nanoparticle cluster (304) and (306) simultaneously. In an embodiment, only one electron (312) is permitted on any nanoparticle cluster (304) and (306) at any one time. Therefore, during conduction of current through the nano-fluid (302), a single electron (312) hops onto the nanoparticle cluster (304) and (306). The electron (312) does not remain on the nanoparticle cluster (304) and (306) indefinitely, but hops off to either the next nanoparticle cluster (306) and (304) or the collector electrode (104) through collisions resulting from the Brownian motion of the nanoparticle clusters (304) and (306). However, the electron (312) does remain on the nanoparticle cluster (304) and (306) long enough to provide the voltage feedback required to prevent additional electrons (312) from hopping simultaneously onto the nanoparticle clusters (304) and (306). The hopping of electrons (312) across the nanoparticle clusters (304) and (306) avoids resistive heating associated with current flow in a media. Notably, the energy harvesting thermionic device (100) containing the nano-fluid (302) does not require pre-charging by an external power source in order to introduce electrostatic forces. This is due to the device (100) being self- charged with triboelectric charges generated upon contact between the nanoparticle clusters (304) and (306) due to Brownian motion. Accordingly, in exemplary embodiments the electron hopping across the nano-fluid (302) is limited to one electron (312) at a time residing on a nanoparticle cluster (304) and (306).

[0069] As the electron current starts to flow through the nano-fluid (302), a substantial energy flux away from the emitter electrode (102) is made possible by the net energy exchange between emitted and replacement electrons (312). The replacement electrons from an electrical conductor connected to the emitter electrode (102) do not arrive with a value of energy equivalent to an average value of the Fermi energy associated with the material of emitter electrode (102), but with an energy that is lower than the average value of the Fermi energy. Therefore, rather than the replacement energy of the replacement electrons being equal to the chemical potential of the emitter electrode (102), the electron replacement process takes place in the available energy states below the Fermi energy in the emitter electrode (102). The process through which electrons are emitted above the Fermi level and are replaced with electrons below the Fermi energy is sometimes referred to as an inverse Nottingham effect. Accordingly, a low work function value of, for example, about 0.5 eV for the emitter electrode (102) allows for the replacement of the emitted electrons with electrons with a lower energy level to induce a cooling effect on the emitter electrode (102).

[0070] As described this far, the principal electron transfer mechanism for operation of the device (100) is thermionic energy conversion or harvesting. In some embodiments, thermoelectric energy conversion is conducted in parallel with the thermionic energy conversion. For example and referring to FIG. 3, an electron (312) colliding with a nanoparticle cluster (304) and (306) with a first energy may induce the emission of two electrons at second and third energy levels, respectively, where the first energy level is greater than the sum of the second and third energy levels. In such circumstances, the energy levels of the emitted electrons are not as important as the number of electrons.

[0071] In at least one embodiment, either the emitter electrode (102) or the collector electrode (104), or both, include a material in the form of lead selenide telluride (PbSeTe) or lead telluride (PbTe). PbSeTe and PbTe are thermoelectric conversion materials that, when introduced into the emitter electrode (102) during fabrication, allows for emission of electrons from the emitter electrode (102) through thermoelectric electron emission. In some embodiments, the PbSeTe or PbTe is also introduced into the collector electrode (104) during fabrication. Similarly, in some embodiments, the PbSeTe or PbTe is introduced during fabrication into at least a portion of the suspended nanoparticle clusters (304) and (306). Accordingly, the use of the PbSeTe or PbTe of some embodiments described herein increases conversion of thermal energy to electrical energy through further increasing the rate of transfer of electrons through the nano-scale energy harvesting device (100).

[0072] Furthermore, the PbSeTe or PbTe used in some embodiments as described herein may be an n-type compound doped with a transition metal in the form of bismuth (Bi) or antimony (Sb). The doping of the n-type compound of PbSeTe or PbTe with the transition metal further increases conversion of thermal energy to electrical energy through further increasing the rate of transfer of electrons through the nano-scale energy harvesting device (100). Accordingly, introducing PbSeTe or PbTe, doped with the transition metal into the emitter electrode (102), the collector electrode (104), and the nanoparticle clusters (304) and (306), increases conversion of thermal energy to electrical energy through increasing the rate of transfer of electrons through the nano-scale energy harvesting device (100).

[0073] A plurality of energy harvesting thermionic devices (100) is distinguished by at least one embodiment having the thermoelectric energy conversion features described herein.

The nano-fluid (112), (302) is selected for operation of the energy harvesting thermionic devices (100) within one or more temperature ranges. In an embodiment, the temperature range of the associated energy harvesting thermionic device (100) is controlled to modulate a power output of the device (100). In general, as the temperature of the emitter electrode (102) increases, the rate of thermionic emission therefrom increases. The operational temperature ranges for the nano-fluid (302) are based on the desired output of the nano-scale energy harvesting device (100), the temperature ranges that optimize thermionic conversion, the temperature ranges that optimize thermoelectric conversion, and fluid characteristics. Therefore, different embodiments of the nano-fluid (302) are designed for different energy outputs of the device (100).

[0074] For example, in an embodiment, the temperature of the nano-fluid (112), (302) is maintained at less than 250°C to avoid deleterious changes in energy conversion due to the viscosity changes of the dielectric medium (308) above 250°C. In an embodiment, the temperature range of the nano-fluid (302) for substantially thermionic emission only is approximately room temperature ( i.e ., about 20°C to about 25°C) up to about 70-80°C, and the temperature range of the nano-fluid (302) for thermionic and thermo-electric conversion is above 70-80°C, with the principle limitations being the temperature limitations of the materials. In an exemplary embodiment, the nano-fluid (302) for operation including thermoelectric conversion includes a temperature range that optimizes the thermoelectric conversion through optimizing the power density within the energy harvesting thermionic device (100), thereby optimizing the power output of the device (100). In at least one embodiment, a mechanism for regulating the temperature of the first nano-fluid (302) includes diverting some of the energy output, e.g., heat, of the device (100) into the nano fluid (302). Accordingly, the apertures (108) of specific embodiments of the energy harvesting thermionic device (100) may be filled with the nano-fluid (302) to employ thermoelectric energy conversion with thermionic energy conversion above a particular temperature range, or thermionic energy conversion by itself below that temperature range.

[0075] As described herein, in at least one embodiment, the dielectric medium (308) has thermal conductivity values less than about 1.0 watt per meter- Kelvin (W/m K). In at least one embodiment, the thermal conductivity of the dielectric medium (308) is about 0.013 watt per meter- Kelvin (W/m K), as compared to the thermal conductivity of water at about 20 degrees Celsius (°C) of about 0.6 W/m K. Accordingly, the nano-fluid (302) minimizes heat transfer, such as through the apertures (108) of FIG. 1, with low thermal conductivity values. Since the heat transport in a low thermal conductivity nano-fluid (302) can be small, a high temperature difference between the two electrodes, e.g., the electrodes (102) and (104), can be maintained during operation. These embodiments are designed for thermal energy harvesting thermionic devices that employ thermionic emission where minimal heat transfer through the nano-fluid (112), (302) is desired. [0076] As shown in FIG. 1, the energy harvesting thermionic device (100) has an aperture (108) with a distance (110) between electrodes (102) and (104) that is within a range of, for example, about 1 nm to about 20 nm. For electrode separation distances (110) of about 1 nm to about less than 10 nm, thermal conductivity values and electrical conductivity values of the nano-fluid (302) are enhanced beyond those conductivity values attained when the predetermined distance of the cavity (108) is greater than about 100 nm. This enhancement of thermal and electrical conductivity values of the nano-fluid (302) associated with the distance (110) of about 1 nm to 10 nm as compared to the distance (110) of greater than 100 nm is due to a plurality of factors. For example, a first factor involves, but is not limited to, enhanced phonon and electron transfer between the plurality of nanoparticle clusters (304) and (306) within the nano-fluid (302), enhanced phonon and electron transfer between the plurality of nanoparticle clusters (304) and (306) and the first electrode (102), and enhanced phonon and electron transfer between the plurality of nanoparticle clusters (304) and (306) and the second electrode (104).

[0077] A second factor is an enhanced influence of Brownian motion of the nanoparticle clusters (304) and (306) in a confining environment, e.g., a distance (110) less than about 10 nm. As the distance (110) between the electrodes (102) and (104) decreases below about 10 nm, fluid continuum characteristics of the nano-fluid (302) with the suspended nanoparticle clusters (304) and (306) is altered. For example, as the ratio of particle size to volume of the apertures (108) increases, random and convection-like effects of Brownian motion in a dilute solution dominate. Therefore, collisions of the nanoparticle clusters (304) and (306) with the surfaces of other nanoparticle clusters (304) and (306) and the electrodes (102) and (104) increase thermal and electrical conductivity values due to the enhanced phonon and electron transfer.

[0078] A third factor is the at least partial formation of matrices of nanoparticle clusters (304) and (306) within the nano-fluid (302). Under certain conditions, the nanoparticle clusters (304) and (306) will form matrices within the nano-fluid (302) as a function of close proximity to each other, with some of the nanoparticle clusters (308) remaining independent from the matrices. In an embodiment, the formation of the matrices is based on the factors of time and/or concentration of the nanoparticle clusters (304) and (306) in the nano-fluid (302). A fourth factor is the predetermined nanoparticle cluster (304) and (306) density, which in an embodiment is about one mole per liter. Accordingly, apertures (108) with a distance (110) of about 1 nm to less than about 10 nm causes an increase in the thermal and electrical conductivity values of the nano-fluid (302) therein.

[0079] In addition, the nanoparticle clusters (304) and (306) have a small characteristic length or diameter, e.g., about 2 nm, and the clusters (304) and (306) are often considered to have only one dimension. This characteristic length restricts electrons in a process called quantum confinement, which increases electrical conductivity. The collision of particles with different quantum confinement facilitates transfer of charge to the electrodes (102) and (104). The energy harvesting thermionic device (100) has an enhanced electrical conductivity value greater than about 1 Siemens per meter (S/m) as compared to the electrical conductivity of drinking water of about 0.005 S/m to about 0.05 S/m. Also, embodiments of device (100) with the enhanced thermal conductivity have a thermal conductivity value greater than about 1 W/m-K as compared to the thermal conductivity of water at 20 degrees Celsius (°C) of about 0.6 W/m-K.

[0080] Thermionic emission of electrons (312) from the emitter electrode (102) and the transfer of the electrons (312) across the nano-fluid (302) from one nanoparticle cluster (304) and (306) to another nanoparticle cluster (304) and (306) through hopping are both quantum mechanical effects.

[0081] Release of electrons from the emitter electrode (102) through thermionic emission as described in embodiments disclosed herein is an energy selective mechanism. A Coulombic barrier in the apertures (108) between the emitter electrode (102) and the collector electrode (104) is induced through the interaction of the nanoparticles (304) and (306) with the electrodes (102) and (104) inside the apertures (108). The Coulombic barrier is at least partially induced through the number and material composition of the plurality of nanoparticle clusters (304) and (306). The Coulombic barrier induced through the nano-fluid (302) provides an energy selective barrier on the order of magnitude of about 1 eV. Accordingly, the nano-fluid (302) provides an energy selective barrier to electron emission and transmission.

[0082] To overcome the Coulombic barrier and allow electrons (312) to be emitted from the emitter electrode (102) above an energy level that overcomes the barrier, materials for the emitter electrode (102) and the collector electrode (104) are selected for their work function values and Fermi level values. The Fermi levels of the two electrodes (102) and (104) and the nanoparticle cluster (304) and (306) will try to align by tunneling electrons (312) from the electrodes (102) and (104) to the nanoparticle cluster (304) and (306). The difference in potential between the two electrodes (102) and (104) (described elsewhere herein) overcomes the Coulombic barrier, and the thermionic emission of electrons (312) from the emitter electrode (102) occurs with sufficient energy to overcome the Coulombic block. Notably, and in general, for cooling purposes, removing higher energy electrons from the emitter electrode (102) causes the emission of electrons (312) to carry away more heat energy from the emitter electrode (102) than is realized with lower energy electrons. Accordingly, in exemplary embodiments the energy selective barrier is overcome through the thermionic emission of electrons at a higher energy level than would otherwise occur without the Coulombic barrier.

[0083] Once the electrons (312) have been emitted from the emitter electrode (102) through thermionic emission, the Coulombic barrier continues to present an obstacle to further transmission of the electrons (312) through the nano-fluid (302). In exemplary embodiments, smaller gaps on the order of about 1 nm to about 10 nm as compared to gaps in excess of 100 nm facilitate electron hopping, i.e., field emission, of short distances across the apertures (108). Energy requirements for electron hopping are much lower than the energy requirements for thermionic emission. Therefore, the electron hopping has a significant effect on the energy generation characteristics of the device (100). The design of the nano-fluid (302) enables energy selective tunneling, e.g., electron hopping, that is a result of the barrier (which has wider gap for low energy electrons) which results in electrons above the Fermi level being a principal hopping component. The direction of the electron hopping is determined through the selection of the different materials for the electrodes (102) and (104) and their associated work function and Fermi level values. The electron hopping across the nano-fluid (302) transfers heat energy with electrons (312) across the apertures (108) while maintaining a predetermined temperature gradient such that the temperature of the nano-fluid (302) is relatively unchanged during the electron transfer. Accordingly, the emitted electrons transport heat energy from the emitter electrode (102) across the apertures (108) to the collector electrode (104) without increasing the temperature of the nano-fluid (302).

[0084] Referring to FIG. 4, a diagram (400) is provided to illustrate a schematic view of an embodiment of a manufacturing system (402) for the nano-scale energy harvesting devices (100). The manufacturing system (402) includes a plurality of dispensing stations. In an embodiment, the system (402) includes four dispensing stations including a first dispensing station (404A), a second dispensing station (404_B), a third dispensing station (404c), and a fourth dispensing station (440). In an embodiment, the system (402) may include less than four dispensing stations. In an embodiment, the system (402) may include more than four dispensing stations. Each of the four dispensing stations (404A) - (404c) and (440) as shown are discussed further herein.

[0085] The first dispensing station (404A) is shown herein with a first dispenser (408A).

In an embodiment, the first dispenser (408A) is operatively coupled to a spindle (406A) that rotates about a predetermined axis. In an embodiment, the spindle (406A) is a shaft that is driven by a drive device, e.g., such as but not limited to, an electric stepper motor, a pneumatic motor, a variable frequency drive, and an induction motor. In an embodiment, the first dispenser (408A) and operatively coupled spindle (406A) is controlled through a control system (410) operatively coupled to the first dispensing station (404A). In an embodiment, the control system (410) utilizes a processor to manage operation of the first dispensing station (404A). In an embodiment, the control system (410) includes a distributed control scheme. In an embodiment, the control system (410) includes a programmable logic controller (PLC). In an embodiment, the control system (410) includes one of more field-programmable gate arrays (FPGAs). In an embodiment, the operable coupling of the control system (410) to the first dispenser station (404A) is wireless, wired, or a combination thereof. In an embodiment, the first dispenser (408A) is a guide that receives a first repository (412A) or spool of a first material (414A) that has a first work function value. In an embodiment, the first material (414A) is an emitter electrode (102), including the polyester film backing (116) in contact with the aluminum (Al) layer (118), and a patterned coating of cesium oxide (CS2O) (134) on the Al layer (118). In an embodiment, the first material (414A) is in the form of a nano-web, i.e. a material or materials where a least one of the dimensional measurements is within the nanometer range as described herein. In an embodiment, the first dispensing station (404A) receives and dispenses any material that enables operation of the system (402) as described herein. Accordingly, a first dispensing station (404A) includes a first dispenser (408A) that dispenses an emitter electrode (102) in the form of a nano-web.

[0086] The first dispensing station (404A) also includes a first guide (416A) that includes a spindle (418A) or shaft in operable communication with the first dispenser (408A). In an embodiment, the spindle (418A) is a shaft that rotates about a predetermined axis. In an embodiment, the spindle (418A) is a shaft that is driven by a drive device, e.g., and without limitation, an electric stepper motor, a pneumatic motor, a variable frequency drive, and an induction motor. In an embodiment, the spindle (418A) is controlled through the control system (410) that is operatively coupled to the first dispensing station (404A). In an embodiment, the first guide (416A) is a portion of a larger guide assembly (420A) described further herein. The first guide (416A) provides support to the first material (414A) and leads or otherwise introduces the first material (414A) as it exits, e.g. unspools, from the first repository (412A). In an embodiment, and as discussed further below, the first guide (416A) controls the direction of the first material (414A). The first dispensing station (404A) further includes a first sensing device (422A). In an embodiment, the first sensing device (422A) is a camera that provides visual feedback of the first material (414A) as it unspools from the first repository (412A). In an embodiment, the visual feedback is displayed on an operatively coupled control station (not shown), e.g., a visual display. In an embodiment, the visual feedback is transmitted to the control system (410) for modulating the rotational rate and the alignment of the first dispenser (408A) and the first guide (416A) to maintain an alignment of the first material (414A) within one or more predetermined parameters. In an embodiment, a position sensing instrument such as, and without limitation, a displacement sensor, or a magneto-restrictive position sensor are employed in place of or in combination with the first sensing device (422A). Accordingly, the first guide (416A) is operably coupled to the first dispenser (408A) to maintain alignment of the first material (414A) during operation of the system (402).

[0087] The first dispensing station (404A) includes one or more a first electrospray devices (424A). In an embodiment, the electrospray device(s) are positioned to deposit or apply nanostructures to at least one of the oppositely positioned surfaces of the dispensed material. For example, the dispensing station (404A) may be inverted or rotated up to 180 degrees (not shown) to deposit or apply the nanostructures. In an embodiment, the coating of CS₂O (134) is not positioned on the first material (414A) prior to positioning the first repository (412A) on the first dispenser (408A), and the electrospray device(s) (424A) deposit the coating of CS2O (134) on the first material (414A) to fabricate an emitter electrode (426A), e.g., a nano-web. In an embodiment, the electrospray device(s) (424A) deposit any material on the first material (414A) that enables operation of the system (402) as described herein. In an embodiment, with the coating of CS2O (134) previously positioned on the first material (414A), the electrospray devices (424A) are idle. In an embodiment, each electrospray device (424A) is a nano-scale electrospray deposition apparatus that produces an expelled stream of droplets (428A) that is sufficiently focused to provide deposition control and accuracy on the nano-scale level. In an embodiment, the first dispensing station (404A) includes two or more electrospray devices (424A) arranged in an array. In an embodiment, the first dispensing station (404A) includes more or less than two devices (424A). In an embodiment, the first dispensing station (404A) includes more than one array of electrospray devices (424A). In an embodiment, the electrospray device(s) (424A) are operably coupled to the control system (410) to modulate the rate and direction of deposition of CS O (134) on the first material (414A) to form the emitter electrode nano- web (426A)· In an embodiment, the stream of droplets (428A) is one of intermittent and continuous, or a combination thereof, for each of the individual electrospray devices (424A) as a function of the desired pattern on the first layer (118). The deposition of the CS O (134) on the first layer (118) contributes to a corresponding work function value. Accordingly, the first dispensing station (404A) deposits or selectively deposits a coating of CS O (134) on those embodiments of the first material (414A) that are positioned in communication with the first dispenser (408A).

[0088] The first dispensing station (404A) further includes a second sensing device (430A), that in an embodiment is similar to the first sensing device (422A). The second sensing device (430A) is operably coupled to the control system (410) to provide real-time feedback of the application and coating of CS O (134) on the emitter electrode nano-web (426A). In an embodiment, the first dispensing station (404A) includes a high voltage (HV) electro-magnetic (EM) field generation device (432A) that generates an HVEM field that facilitates precise deposition of the CS O coating (134) on the first layer (118). In an embodiment, the field generation device (432A) is operably coupled to the control system (410). Accordingly, the first dispensing station (404A) dispenses a first material (414A) in the form of an emitter electrode nano-web (426A) and fabricates the emitter electrode nano-web (426A) through deposition of a coating of CS O (134) on the first layer (118).

[0089] The manufacturing system (402) also includes the second dispensing station (404_B) that is similarly configured to the first dispensing station (404A). In an embodiment, the second dispensing station (404_B) includes a second dispenser (408_B) and an operatively coupled second spindle or shaft (406_B). The second dispenser (408_B) receives and dispenses a second repository (412_B) of a second material (414_B). The second dispensing station (404_B) also includes a second guide (416_B) that includes a second spindle (418_B), where the second guide (416_B) is a portion of the guide assembly (420_B). The second dispensing station (404_B) further includes a third sensing device (422_B) that is similar to the first sensing device (422A). The second dispensing station (404_B) further includes a second electrospray device (424_B), that in an embodiment may be a plurality of electrospray devices that fabricate a collector electrode nano-web (426_B) through a second expelled stream of droplets (428_B) when in service. The second dispensing station (404_B) also includes a fourth sensing device (430_B) that is similar to the second sensing device (430A) and a second HVEM field generation device (432_B) that is similar to the first HVEM field generation device (432A). In an embodiment, with the coating of CS O (164) previously positioned on the second material (414_b), the electrospray device(s) (424_B) are idle. In an embodiment, the second electrospray device(s) (424_B) deposit the coating of CS O (164) on the second material (414_B). The deposition of the CS O (134) on the second layer (148) contributes to a corresponding work function value, which in an embodiment is decreased from approximately 5.65 eV for Pt (or 4.28 eV for Al) to a work function value of about 0.88 eV. Similarly, in an embodiment, the second layer (148) is comprised of gold (Au), and deposition of the CS O (134) on the second layer (148) decreases the work function value, which in an embodiment is decreased from approximately 5.45 eV for Au to a work function value of about 0.66 eV. In a manner similar to that of the first dispensing station (404A), the second dispenser (408_B), the spindle (418_B) of the second guide (416_B), the third sensing device (422_B), the second electrospray device(s) (424_b), the fourth sensing (430_B), and the second HVEM field generation device (432_B) are operably coupled to the control system (410). Accordingly, the second dispensing station (404_b) introduces the collector electrode (104) in the form of a nano-web (426_B) to the manufacturing process as described herein, where the work function value of the collector electrode nano-web (426_B) is different from, e.g., greater or less than, the work function value of the emitter electrode nano- web (426A).

[0090] The manufacturing system (402) further includes the third dispensing station (404c) that is similar to the first and second dispensing stations (404A) and (404_B), respectively. In an embodiment, the third dispensing station (404c) includes a third dispenser (408c) and an operatively coupled third spindle or shaft (406c). The third dispenser (408c) receives and dispenses a third repository (412c) of a third material (414c). The third dispensing station (404c) also includes a third guide (416c) that includes a spindle (418c), where the third guide (416c) is a portion of the guide assembly (420c). The third dispensing station (404c) further includes a fifth sensing device (422c) that is similar to the first and third sensing devices (422A) and (422_B), respectively. A third electrospray device (424c), which in an embodiment may include a plurality of electrospray devices, fabricates a spacer nano-web (426c) through a third expelled stream of droplets (428c) when in service. The third dispensing station (404c) also includes a sixth sensing device (430c) that monitors the deposition of the nano-fluid (302) in the apertures (206) of the spacer (200). The third dispensing station (404c) also includes a third HVEM field generation device (432c) to facilitate precise deposition of the nano-fluid (302) in the apertures (206). The third electrospray device(s) (424c) deposits the nano-fluid (302) into the apertures (206).

Therefore, in an embodiment, the third electrospray device(s) (424c) have a different configuration than that of the first and second electrospray devices (424A) and (424_B), respectively. In an embodiment, the nano-fluid (302) does not require a drying time as does the CS2O (134) and (164) (see FIG. 5), because the nano-fluid (302) remains in a fluid form. In a manner similar to that of the first and second dispensing stations (404A) and (404_B), respectively, the third dispenser (408c), the spindle (418c) of the third guide (416c), the fifth sensor (422c), the third electrospray device(s) (424c), the sixth sensor (430c), and the third HVEM field generation device (432c) are operably coupled to the control system (410). In an embodiment, the emitter electrode nano-web (426A) and the collector electrode nano-web (426_B) are offset from the separation material nano-web (426c) during the manufacturing process performed by the manufacturing system (402) as shown and described in FIGS. 2A and 2B. Therefore, alignment of the three nano-webs (426A), (426_b), and (426c) as described herein includes the offsets. Accordingly, the third dispensing station (404c) introduces the spacer (200) in the form of a nano- web (426c) to the manufacturing process as described herein, where the spacer nano-web (426c) is positioned between the emitter electrode (426A) and the collector electrode (426_B).

[0091] Rather than a nano-web material-based third dispensing station (404c), in an embodiment, the third dispensing station (404c) may be spray based. In an embodiment, the spacer material is sprayed onto the emitter electrode nano-web (426A) downstream from the electrospray devices (424A) where the CS2O coating (134) is positioned on the first material (414A) to at least partially cover or communicate with the coating (134). The spacer material is electro sprayed through one or more electrospray devices similar to device (424A). One or more spacer material electrospray devices are positioned sufficiently downstream from the electrospray devices (424A) to permit adequate drying of the coating (134) (see FIG. 5). The spacer material is patterned on the emitter electrode nano-web (426A) to define apertures similar to apertures (206). Further downstream of the spacer material spray device(s), the third electrospray device(s) (424c) is positioned to place the nano-fluid (302) into the apertures, where the device(s) (424c) are positioned sufficiently downstream from the spacer material spray devices to allow the spacer material to sufficiently dry prior to receiving the nano-fluid (302) (see FIG. 5). In an embodiment, the spacer material is sprayed onto the collector electrode (426_B) downstream of where the CS2O coating (164) is positioned on the second material (414_B) through the electrospray device(s) (424_B) where the process is similar to that for the emitter nano- web (426A). In an embodiment, to enable the offsets of the of the emitter electrode (426A) and the collector electrode (426_B) with respect to the separation material, each of the electrodes (426A) and (426_B) receive application of a portion of the separation material spray in a pattern that effectively represents the offsets produced with the separation material (426c) (see FIGS. 2A and 2B). Accordingly, the spacer material may be in the form of a nano-web or a sprayed material.

[0092] The manufacturing system (402) further includes the fourth dispensing station (440) that, in an embodiment, is configured differently than the first, second, and third dispensing stations (404A), (404_b), and (404c), respectively. In an embodiment, the fourth dispensing station (440) is configured similar to the first, second, and third dispensing stations (404A), (404_b), and (404c). The fourth dispensing station (440) is shown with a fourth dispenser (442) that receives a fourth repository of material (444), where the fourth material (446) is a casing, or sheathing material (446) that encases the combined electrodes (426A) and (426_B) and separation material (426c), as discussed further herein. The fourth dispensing station (440) includes a seventh sensing device (448) that is similar to the first through sixth sensors (422A), (430A), (422_b), (430_b), (422_C), and (430c), respectively. The seventh sensing device (448) monitors the dispensing of the casing material (446) from the fourth dispenser (442) by the fourth dispenser (442). The fourth dispensing station (440) further includes a fourth guide (450) that includes a fourth spindle (452), where the fourth guide (450) is a portion of guide assembly (420). The fourth dispenser (442), the spindle (452), and the seventh sensing device (448) are operatively coupled to the control system (410). Accordingly, the manufacturing system (402) includes a fourth dispensing station (440) that dispenses a casing material (446) for manufacturing the energy harvesting thermionic device (100).

[0093] The manufacturing system (402) as shown and described herein includes a guide system that includes guide assemblies (420A), (420_b), (420_C) and (420) that direct the flow of the corresponding materials (426A), (426_B), (426_C), and (446), respectively. In an embodiment, the guide system includes a centrally positioned element (460), hereinafter referred to as a center wheel, that is in operable communication with the dispensing stations (404A), (404_B), (404_C), and (440) such that the dispensing stations (404A), (404_B), (404_C), and (440) are in operable communication with each other. In an embodiment, the center wheel (460) is an idler wheel that includes an idler spindle (462) that provides alignment and free rotation of the wheel (460). In this embodiment, a device external to wheel (460) provides a force to pull the four materials (426A), (426_B), (426_C), and (446) as discussed further herein. In an embodiment, the spindle (462) is operably coupled to the control system (410) to modulate the position of the wheel (460) with respect to the dispensing stations (404A), (404_B), (404_C), and (440). In an embodiment, the wheel (460) is a drive wheel that is driven through the spindle (462) that is rotatably coupled to a drive device (not shown), e.g., a motor as described herein for the spindle (408A)· In this embodiment, the spindle (462) is operably coupled to the control system (410). The wheel (460) is operably coupled to the dispensing stations (404A), (404_B), (404_C), and (440), respectively, through the respective guide rollers (416A), (416_B), (416_C), and (452), that are portions of the guide system.

[0094] The guide assemblies (420A), (420_B), (420_C) and (420) position the materials (426A), (426_B), (426_C), and (446) at a joint proximal position (464) thereof to produce a fabricated energy harvesting thermionic material (466) that is used to manufacture the energy harvesting thermionic devices (100) as described further herein. As used herein, the term “joint proximal position” refers to portion of the manufacturing system (402) where two or more of the materials (426A), (426_B), (426_C) and casing material (446) come into contact proximate to the wheel (460). The guide assembly (420) also positions the second material, e.g. the collector nano-web, (426_B) in a joint proximal position (468) with the third material, e.g. spacer nano-web, (426c)· The guide assemblies (420A), (420_B), (420_C) and (420) further position the nano-web materials (426_B) and (426c), respectively, in a joint proximal position (470) with the first material, i.e., the emitter electrode nano-web (426A)· The guide system further includes a fifth guide (472) that includes a spindle (474). The fifth guide (472) is similar to the guide assemblies (416A), (416_B), (416_C), and (450). The spindle (474) is similar to spindles (418A), (418_B), (418_C), and (452). The fifth guide (472) provides alignment to the fabricated energy harvesting thermionic material (466) and directs the material to a receiving station (480), i.e., a receiver (480). In an embodiment, the fifth guide (472) is coupled to a drive device, e.g., a motor similar to that described for spindle (408A)· In this embodiment, the fifth guide (472) provides the motive force to pull the material (466) and drive rotation of the wheel (460), which in turn provides a pulling force on the nano-web materials (426A), (426_B), (426_C), and casing material (446) to rotate the respective guides (416A), (416_B), (416c), and (450), and the respective repositories (412A), (412_B), (412_C), and (444). The fifth guide (472) also provides the force necessary to push the material (466) into the receiver (480). Also, in this embodiment, the fifth guide (472) is operably coupled to the control system (410) to regulate the speed of the spindle (474) and/or the position of the fifth guide (472). Accordingly, the guide assemblies (420A), (420_B), (420_C) and (420) guide the materials (426A), (426_B), (426_C), and (446) to be joined at proximal positions (468), (470), and (464) to fabricate the energy harvesting thermionic material (466) that is used to manufacture the electric power harvesting devices (100).

[0095] The receiver (480) is in operable communication, shown herein as in serial communication, with the fifth guide (472) and receives the energy harvesting thermionic material (466) therefrom. In an embodiment, the receiver (480) includes a cutting device (482) that severs the incoming material (466) into planar severed portions, i.e., a sheet of material (466), with predetermined dimensions. In an embodiment, the sheet is approximately 36 inches (0.91 meters (m)) by approximately 4 inches (10.2 centimeters (cm) by approximately 0.079 inches (2 mm), although these dimensions should not be considered limiting. The receiver (480) also includes a winding device (484) operably coupled to the cutting device (482). The winding device (484) receives the severed sheets of material (466) and forms each severed sheet into an arcuate product (see FIGS. 6 and 7) through winding the material (466) on a winding shaft (486). In an embodiment, the winding shaft (486) is approximately 1/8* (0.125) of an inch (3.175 mm) in diameter and is at least partially threaded, although the size and threading should not be considered limiting. In an embodiment, a structural member (see FIGS, 6 and 7) acts as the shaft (484) and the shaft (484) remains coupled to the wound material (466). In an embodiment, the receiver does not include a cutting device and the material (466) is wound on the winder (484) for storage or further manufacturing. In an embodiment, the receiver (480) does not include the winder (484) and the severed sheets of material (466) that are generated by the cutting device (482) are collected for further manufacturing into a planar electric power harvesting device (see FIG. 8) or for transport to a remote winding device for further manufacturing into an arcuate device (see FIGs. 6 and 7). In an embodiment, the receiver (480) includes a drive device (not shown) similar to that described for the fifth guide (472) to pull the material (466) into the receiver (480). Accordingly, as shown and described, but not limited, the manufactured material (466) is formed into arcuate shapes or profiles.

[0096] Referring to FIG. 5, an enlarged schematic view (500) is provided to illustrate a portion of a manufacturing system (502), specifically, a second dispensing station (504_B). A collector electrode material (514_B) is dispensed from a collector electrode material repository (512_b) and is dispensed to a guide (516_B) with a third sensing device (522_B) providing alignment feedback to the control system (410). The guide (516_B) leads or otherwise introduces the material (514_B) to traverse an electrospray device (524_B) to receive the coating of CS O (164), which in an embodiment is a patterned coating. The material (514_B) receives the coating (164) from the device (524_B) in the form of a second expelled fluid, e.g., stream, of droplets (528_B). A nozzle (590) is positioned a distance (592) from the material (514_B) to deposit the coating (164) at a first position (594). In an embodiment, the distance (592) is pre determined or configurable. The distance (592), sometimes referred to as a “critical distance,” is based on factors that include, without limitation, a composition of the material being sprayed, a composition of the receiving substrate, a velocity of the coating droplets (528_B), a concentration of the droplets (528_B), and a dispersion of the droplets (528_B) such that a pattern or precise pattern of the coating (164) is positioned on the electrode material (514_B) to fabricate a collector electrode nano-web (526_B).

[0097] A fourth sensing device (530_B) monitors the coating (164) on the collector electrode (526_B), e.g., nano-web, and the distance (592). In an embodiment, the feedback from the fourth sensing device (530_B) is transmitted to the control system (410) to regulate the position of the electrospray device (524_B) to modulate the distance (592). In an embodiment, the feedback from the sensing device (530_B) may be used to regulate one or more of, without limitation, the speed of material (514_B) dispensed from the repository (512_b), the position of the repository (512_B), the position of the guide (516_B), and the position of a center wheel (560). Accordingly, the distance (592) between the electrospray device (524_b) and the material (514_B) is subject to control and management.

[0098] A distance (596) between the first position (594) and an associated joint proximal position (568) where collector electrode (526_B) is contacted by spacer nano-web (526c) is determined, or in an embodiment pre-determined, to allow sufficient drying time for the CS O coating (164). The distance (596) is based on one or more of, without limitation, a composition of the material being sprayed, a composition of the receiving substrate, the amount of material sprayed, and the speed of the collector electrode (526_B). Similarly, a distance between the deposition of the CS2O coating (134) on the emitter electrode (426A) and the joint proximal position (464) is determined. In an embodiment, the distance (596) may be regulated through modulation of the positions of the guide (516_B) and the center wheel (560). In an embodiment, meeting the requirement of the drying time is accomplished through modulation of the speed of the repository (512_B). Accordingly, the manufacturing system (502) provides for an adequate drying time for the CS2O coatings (164) and (134).

[0099] As described elsewhere herein, in an embodiment, rather than a nano-web material-based third dispensing station (404c), the third dispensing station is used to spray the spacer material onto either the emitter or collector electrode nano-web (426A) and (426_B), respectively. The spacer material is electro sprayed through one or more electrospray devices similar to devices (424A). The spacer electrospray devices are positioned downstream from the electrospray devices (424A) and (424_B), respectively, to permit adequate drying of the coating (134) or (164), respectively. The spacer spray material is positioned on the first material (414A) or the second and the second material (414_B), respectively, to at least partially cover the coating (134) or (164), respectively. In a manner similar to that for the CS2O coatings (134) and (164), the spacer material electrospray devices are positioned sufficiently apart from the wheel (560) and the associated joint proximal position (468), which in an embodiment may be less than 1.0 cm, to permit adequate drying of the sprayed spacer material. Accordingly, a predetermined distance is positioned between the electrospray devices for spraying the spacer material and the joint proximal position to allow for adequate drying of the spacer material.

[0100] Referring to FIG. 6, a diagram (600) is provided illustrating a schematic perspective view of an embodiment of a nano-scale energy harvesting thermionic device (690) that may be manufactured as described herein. The thermionic device (690) of FIG. 6 has an arcuate profile. The device (690) is not shown to scale. The device (690), also referred to herein as a power generation device, is manufactured by the manufacturing system (402) with a plurality of layers of materials, as described in detail herein. In an embodiment, the device (690) is manufactured with a plurality of separate layers, shown herein as four separate layers. A first layer (602) is referred to as a casing or sheathing that protects one or more of the inner layers and facilitates heat transfer in and out of the device (690). In an embodiment, the casing (602) is fabricated from the casing material (446). In an embodiment, the first layer (602) is manufactured from a thermally conductive and electrically insulating material. A second layer (604) includes the emitter electrode fabricated from the emitter electrode nano- web (426A)· A third layer (606) includes the separation material (also referred to herein as a standoff and spacer) fabricated from the spacer nano- web (426c)· In an embodiment, the third layer (606) is referred to herein as a spacer. A fourth layer (608) includes the collector electrode fabricated from the collector electrode nano-web (426_B). The emitter electrode (604), the spacer (606), and the collector electrode (608) are fabricated and configured as shown and described in FIGS. 1-5. The nano-fluid (112), (302) is positioned in apertures (108) and (206) of the separation material (606), e.g., third layer. The outer casing (602), i.e., the first layer, is in direct contact with the emitter electrode (604), i.e., the second layer. The emitter electrode (604), i.e., the second layer, and the collector electrode (608), i.e., the fourth layer, are in direct contact with the spacer (606). Layers (602), (604), (606), and (608) are shown peeled away for clarity and illustrative purposes. In an embodiment, the layers (602), (604), (606), and (608) define a composite layer (610) of the electric power generation material (466) that is used to manufacture the energy harvesting thermionic devices (690). Accordingly, the outer casing (602) is in contact with the emitter electrode (604) to provide heat transfer, protective, and sealing features to the device 690 (or (100) in relation to FIG. 1).

[0101] The device (690) is shown herein with an arcuate or cylindrical configuration with a defined radius (612) extending from an axial centerline (614) to an outermost surface (616) of the device (690). The axial centerline (614) extends parallel to the Z-axis and the radius (612) is defined in a plane defined by the X-axis and Y-axis such that the radius (612) and axial centerline (614) are orthogonal. The device (690) includes an axial aperture (618), shown in broken lines or phantom, coincident with the axial centerline (614) extending from a first base area (620) to an opposing second base area (622). In an embodiment, a structural member (624) is positioned in and received by the axial aperture. The structural member (624) extends from the first base area (620) to the second base area (622), and in an embodiment, the structural member (624) protrudes from one or both of the base areas (620) and (622). In an embodiment, the structural member (624) is fabricated from one or more materials that are both thermally and electrically conductive, as well as chemically compatible with the materials of the layers (602), (604), (606), and (608). In other embodiments, the structural member (624) is fabricated from materials that are either thermally or electrically conductive. In an embodiment, layers (602), (604), (606), and (608) are wrapped around the structural member (624) during winding of the composite layer (610) about the member (624) in the receiver (480) with winding device (484). In an embodiment, the structural member (624) is inserted into the axial aperture (618) with an insertion device (see FIG. 11). Accordingly, the structural member (624) is configured to transfer heat energy and electrical energy generated within the device (690) away from the device (690).

[0102] The fourth layer (608), i.e., the collector electrode, is electrically coupled to the structural member (624) to provide at least a partial electrical flow path. The composite layer (610) extends from the structural member (624) in a spiral configuration, where the spiral configuration has a common center defined by the axial centerline (614) to further define a concentric configuration. The axial aperture (618) further defines a toroidal or elongate oval configuration with respect to the spiral wound configuration of the composite layer (610). Accordingly, the arcuate energy harvesting thermionic device (690) has features that are spiral, concentric, cylindrical, and toroidal.

[0103] In an embodiment, the arcuate energy harvesting thermionic device (690) has a length (626) measured along the Z-axis of approximately 10 mm to about 2.0 m. The radius (612) of device (690) is approximately 0.635 cm (about 0.25 inch) to about 5.1 cm (about 2.0 inches). A thickness (628) of the composite layer (610) is approximately 0.005 mm to about 2 mm. A thickness (630) of the collector electrode (608) is approximately 0.005 mm to about 2.0 mm. A thickness (632) of the spacer (606) is approximately 1.0 nm to about 10 microns.

A thickness (634) of the emitter electrode (604) is approximately 0.005 mm to about 2.0 mm. A thickness (of the outer casing (602) is approximately 0.005 mm to about 2.0 mm. A length of the composite layer (610) of the embodiment, if laid out flat from the spiral configuration, is approximately 5.1 cm (about 2.0 inches) to approximately 122 cm (about 48.0 inches). Other embodiments include any dimensional characteristics that enable manufacturer and operation of the arcuate shaped device (690) as described herein.

[0104] A single device (690) can generate a voltage within a range extending between about 0.5 volt and 1.0 volt, depending on the contact potential difference (discussed further herein) induced between the emitter electrode (604) and the collector electrode (608) as a function of the materials used for each. In an embodiment, the device (690) generates about

0.90 volt. The device (690) can generate an electrical current within a range of approximately

5 amperes (amps) to approximately 10 amps. In an embodiment, the device (690) generates about 7.35 amps. Further, in an embodiment, the device (690) generates approximately 2.5 watts to approximately 10 watts. In an embodiment, the device (690) generates about 6.6 watts. A plurality of the devices (690) may be electrically connected in series for a specific voltage or in parallel for a specific current, or in series and parallel to satisfy both the voltage and current requirements. Accordingly, as described further herein, the arrangements of the devices (690) are scalable to provide sufficient electrical power from the watt range to the megawatt range for a variety of applications.

[0105] The structural member (624) performs both heat transfer and electrical conduction actions when the arcuate energy harvesting thermionic device (690) is in service generating electricity. In addition, the structural member (624) provides structural integrity, and an anchor for an end cap (not shown). The structural member (624) is electrically coupled to an external circuit (not shown) to transmit the electrical power generated within the device (690) to loads on the external circuit. The structural member (624) is also coupled to a either a heat exchanger or a heat sink through a heat transfer member (not shown). In an embodiment, the heat transfer member (not shown) is fabricated from an electrically non-conductive material that has sufficient heat transfer characteristics to maintain the device (690) within a predetermined temperature range. In an embodiment, heat transfer member (not shown) is fabricated from, for example, but not limited to, graphene, carbon composite, and similar materials. Accordingly, the structural member (624), which is shown and described herein as having dual purposes, is positioned within the axial aperture (618) during the manufacturing process as described further herein.

[0106] The energy harvesting thermionic device (690) generates electric power through harvesting heat energy (664). The emitter electrode (604) receives heat energy (664) from sources that include, without limitation, heat generating sources and ambient environments, and generates an electric current that traverses the apertures (206) via the nanoparticle clusters (304) and (306) in the form of the electrons (312). The electric current reaches the collector electrode (608) and the current is transmitted through the structural member (624) to the external circuit to power the loads therein. In an embodiment, the device (690) generates electrical power through placement in ambient, room temperature environments.

Accordingly, the device (690) harvests heat energy (664), including waste heat, to generate useful electrical power.

[0107] Referring to FIG. 7, a diagram (700) is provided illustrating a perspective view of an arcuate energy harvesting device (790). In an embodiment, the device (790) is similar to the device (690). In an embodiment, an outer casing (702) includes multiple layers (602) of the outer casing material (446) to fabricate the outer casing (702) with an enhanced robustness. The outer casing (702) of the device (790) includes an external surface (740) that includes a seam (742) defined by one or more layers (602) of the outer casing (702). In an embodiment, the seam (742) is defined by the composite layer (610). The seam (742) receives a sealant (744) to prevent ingress of contaminants and egress of device materials through the seam (742). In an embodiment, the sealant (742) is non-conductive to prevent short circuiting of the electrodes (604) and (608). In an embodiment, the sealant (744) is antimony-based. In another other embodiment, the sealant (744) is manufactured from a material that enables operation of the arcuate energy harvesting thermionic devices (690) and (790) as described herein.

[0108] A first base area (720) receives a sealant (746) that extends between a rim (748) defined by the outer casing (702) and a structural member (724) that is similar to the structural member (624). In an embodiment, the sealant (746) is substantially similar to the sealant (744). In an embodiment, the sealant (746) is different from the sealant (744). The sealant (746) is also applied to a second base area (722), where the second base area (722) has a similar configuration to the first base area (720). The sealant (746) functions to provide protection of the electrodes (604) and (608), the spacer (606), and the nano-fluid (302) from environmental factors, such as debris, that may induce a short circuit between the electrodes (604) and (608) or contaminate the nano-fluid (302). In an embodiment, the sealants (744) and (746) are applied to the device (790) after the structural member (724) is inserted into the axial aperture (618) during the manufacturing process as described further herein. In addition, as described herein with respect to FIGS. 2A and 2B, the electrodes (604) and (608) (equivalent to electrodes (262) and (264), respectively) are offset by distances (236) and (248), respectively, from the spacer (606). Therefore, the non-conducting sealant (746) resides around the lateral side edge (230) of the electrode (102) and the lateral side edge (242) of the electrode (104) that extend distances (236) and (248) beyond the spacer (606), respectively. Accordingly, the energy harvesting thermionic device (790) is shown herein with the sealants (744) and (746) that provide environmental protections for the device (790) and electrical insulation for the electrodes (604) and (608).

[0109] Referring to FIG. 8, a diagram (800) is provided illustrating a schematic perspective view of an embodiment of a (nano- scale) energy harvesting thermionic device (890) for generating electrical power, hereinafter referred to as device (890) that may be manufactured as described herein, e.g., having a planar profile. The device (890) is not shown to scale. In an embodiment, the device (890) is manufactured by the manufacturing system (400) with a plurality of layers of materials similar to that described for arcuate device (690). The device (890) includes a composite layer (810) that is similar to the composite layer (610), where the layers (602), (604), (606), and (608) similarly define the composite layer (810) of the electric power generation material (466) that is used to manufacture the planar electric power harvesting devices (890). Accordingly, the planar device (890) includes the sequence of adjacently positioned layers (602), (604), (606), and (608) as described for the arcuate device (690).

[0110] The device (890) is shown herein with a planar or rectangular configuration with a first dimensional value (812A) extending through an axial centerline (814) from a first external surface (816A) to a second external surface (816_B) of the device (890). The axial centerline (814) extends parallel to the Z-axis and the first dimensional value (812A) extends parallel to the Y-axis. The device (890) includes a second dimensional value (812_B) that extends parallel to the X-axis and a third dimensional value (812c) that extends parallel to the Z-axis. The device (890) includes an axial aperture (818) coincident with the axial centerline (814) extending from a first base area (820) to an opposing second base area (822). In an embodiment, a planar structural member (not shown) similar to the cylindrical structural member (624) with the exception of the shape is inserted into and received by the axial aperture (818) in a manner similar to the structural member (624) inserted into the axial aperture (618) for the device (690). The planar structural member extends from the first base area (820) to the second base area (822), and in an embodiment, the planar structural member protrudes from one or both of the base areas (820) and (822). In an embodiment, the layers (604) to (608) are wrapped around the structural member during winding of the composite layer (610) about the planar structural member in the receiver (480) with a winding device similar to the winding device (484), but configured to wind the electric power generation material (466) into the configuration shown in FIG. 8. In an embodiment, the planar structural member is inserted into the axial aperture (818) with an insertion device (see FIG. 11). Accordingly, the planar structural member is configured to transfer heat energy and electrical energy generated within the device (890) away from the device (890). [0111] The device (890) includes a planar section (850) defined by the axial aperture (818) and two semi-cylindrical sections (852A) and (852_B). The semi-cylindrical sections (852A) and (852_B) define third and fourth external surfaces (816c) and (816_D), respectively. The planar device (890) is manufactured through a process where the electric power generation material (466) is successively wrapped about the axial aperture (818) such that the material (466) defines successive overlapping composite layers (810). The overlapping composite layers (810) have a planar configuration in the planar portion (850) and have a 180-degree turn on each semi-cylindrical section (852A) and (852_B) such that the composite layer (810) is continuous from the axial aperture (818) to a seam (842) defined at the first external surface (816A) by the planar section (850) and the semi-cylindrical section (852_B). The two semi-cylindrical sections (852A) and (854_B) and the planar section (850) define a quasi-rectangular spiral configuration (discussed further below). Accordingly, the planar device (890) is manufactured with a continuous extent of the electric power generation material (466) to define semi-cylindrical sections (852A) and (854_B) and a planar section (850).

[0112] The fourth layer (608), i.e., the collector electrode, is electrically coupled to the planar structural member to provide at least a partial electrical flow path. The composite layer (810) extends from the planar structural member in a quasi-rectangular spiral configuration, where the quasi-rectangular spiral configuration has a common center defined by the axial centerline (814) to further define a quasi-rectangular concentric configuration. The axial aperture (818) further defines a toroidal configuration with respect to the quasi-rectangular spiral wound configuration of the composite layer (810). Accordingly, the planar energy harvesting thermionic device (890) has features that are spiral, concentric, rectangular, and toroidal.

[0113] In an embodiment, the device (890) has a first dimensional value (812A) of approximately 0.5 mm to about 5.0 mm, a second dimensional value (812_B) of approximately 30.0 mm to about 150 mm, and a third dimensional value (812c) of approximately 20.0 mm to about 300 mm. In an embodiment, a length of the composite layer (810), if laid out flat from the quasi-rectangular spiral wound configuration, is approximately 10 mm to about 2.0 m. Other embodiments include any dimensional characteristics that enable manufacturer and operation of the device (890) as described herein. [0114] In an embodiment, one of the devices (890) can generate a voltage within a range extending between about 0.5 volts and 1.0 volts, depending on the contact potential difference (discussed further herein) induced between the emitter electrode (604) and the collector electrode (608) as a function of the materials used for each. In an embodiment, the device (890) generates about 0.90 volts. In an embodiment, the device (890) can generate an electrical current within a range of approximately 5 amperes (amps) to approximately 10 amps. In an embodiment, the device (890) generates about 7.35 amps. Further, in an embodiment, the device (890) generates approximately 2.5 watts to approximately 10 watts. In an embodiment, the device (890) generates power equivalent to or about the same as the device (690) shown in FIG. 6. A plurality of the devices (890) may be electrically connected in series for a specific voltage or in parallel for a specific current, or in series and parallel to satisfy both the voltage and current requirements. Accordingly, as described further herein, the arrangements of the devices (890) are scalable to provide sufficient electrical power from the watt range to the megawatt range for a variety of applications.

[0115] The energy harvesting thermionic device (890) generates electric power through harvesting heat energy (864). The emitter electrode (404) receives heat energy (864) from sources that include, without limitation, heat generating sources and ambient environments, and generates an electric current that traverses the apertures (206) via the nanoparticle clusters (304) and (306) in the form of the electrons (312). The electric current reaches the collector electrode (408) and the current is transmitted through the planar structural member to an external circuit to power the loads thereon. In an embodiment, the device (890) generates electrical power through placement in ambient, room temperature environments. Accordingly, the device (890) harvests heat energy (864), including waste heat, e.g., heats the ambient environment, to generate useful electrical power.

[0116] The outer casing layer (602) of the device (890) defines the first external surface (816A), the second external surface (816B), the third external surface (816c), and the fourth external surface (816D). In an embodiment, an overlap of the first and fourth external surfaces (816A) and (816D), respectively, define the seam (842). The seam (842) is similar to the seam (742) for the cylindrical device (790) and the seam (842). In an embodiment, the seam (842) receives a sealant (not shown in FIG. 8) similar to the sealant (744) to prevent ingress of contaminants and egress of device materials through the seam (842). In an embodiment, the outer casing (602) of the device (890) includes multiple layers of outer casing material (446) to fabricate the outer casing (602) with an enhanced robustness.

[0117] In an embodiment, the first base area (820) receives a sealant (not shown in FIG.

8) that is similar to the sealant (746). In an embodiment, the sealant is also applied to the second base area (822), where the second base area (822) has a similar configuration to the first base area (820). The sealant functions to provide protection of the electrodes (604) and (608), the spacer (606), and the nano-fluid (302) from environmental factors, such as debris, that may induce a short circuit between the electrodes (604) and (608) or contaminate the nano-fluid (302). In an embodiment, the sealant or sealants are applied to the device (890) after the planar structural member is inserted into the aperture (818) during the manufacturing process as described further herein. In addition, as described herein with respect to FIGS. 2A and 2B, the electrodes (604) and (608) (equivalent to electrodes (262) and (264), respectively) are offset distances (236) and (248), respectively, from the spacer (606). Therefore, the non-conducting sealant resides around the lateral side edges (230) of the electrode (262) and the lateral side edges (242) of the electrode (264) that extend distances (236) and (248) beyond the spacer (200), (606), respectively. Accordingly, the energy harvesting thermionic device (890) receives sealants that provide environmental protections for the device (890) and electrical insulation for the electrodes (604) and (608).

[0118] In an embodiment, the arcuate energy harvesting thermionic devices (690) and (790) and the planar energy harvesting thermionic device (890) are manufactured from repositories of materials as shown and described by way of example in FIG. 4. Referring to FIG. 9, a diagram (900) is provided illustrating a perspective view of a first repository (992) of layered materials (902) and (904), i.e., the first and second layers, that may be used to manufacture the devices (690), (790), and (890) as described herein. Referring to FIG. 10, a diagram (1000) is provided illustrating a perspective view of a second repository (1092) of layered materials (1006) and (1008), i.e., the third and fourth layers, that may be used to manufacture the devices (690), (790), and (890) as described herein.

[0119] Referring to FIG. 9, in an embodiment the first layer (902) is equivalent to the outer casing (602) and is hereinafter referred to as the outer casing (902). Similarly, the second layer (904) is equivalent to the emitter electrode (604) and is hereinafter referred to as the emitter electrode (904). The outer casing (902) includes a first surface (970) that defines the external surface (740) of the arcuate devices (690) and (790) and external surfaces (816_A) through (816_D) of the planar device (890). The outer casing (902) also includes a second surface (972) that is opposite to the first surface (970) and contacts the emitter electrode (904). The emitter electrode (904) includes a first surface (974) contacting the second surface (972) of the outer casing (902). The emitter electrode (904) also includes a second surface (976) that is opposite to the first surface (974). In an embodiment, the second surface (976) is at least partially coated with CS O (978), which in an embodiment is pre-applied to the second surface (976). In an embodiment, the CS O (978) is applied to the second surface (976) during manufacturing of the devices (690), (790), and (890).

[0120] Referring to FIG. 10, the third layer (1006) is equivalent to the separation material (606), and is hereinafter referred to as separation material (1006). Similarly, the fourth layer (1008) is equivalent to the collector electrode (608) and is hereinafter referred to as collector electrode (1008). The separation material (1006) includes a first surface (1070) that contacts the second surface (976) of the emitter electrode (904). The separation material (1006) also includes a second surface (1072) that is opposite to the first surface (1070). The collector electrode (1008) includes a first surface (1074) contacting the second surface (1072) of the separation material (1006). The collector electrode (1008) also includes a second surface (1076) that is opposite to the first surface (1074). In an embodiment, the first surface (1074) is at least partially coated with CS O (1078), which in an embodiment is pre-applied to the first surface (1074). In an embodiment, the CS O (1078) is applied to the first surface (1074) during manufacturing of the devices (690), (790), and (890).

[0121] Referring to FIGS. 4, 9, and 10, the manufacturing system (402) may be adapted to use the first repository (992) and the second repository (1092) to fabricate the electric power generation material (466). In an embodiment, the first repository (992), including the casing layer (902) and the emitter electrode layer (904), is positioned on the first, third, or fourth dispensing stations (404_A), (404_C), and (444), respectively. The second repository (1092) including the spacer layer (1006) and the collector electrode layer (1008) is positioned on the second, third, or first dispensing stations (404_B), (404_C), and (404_A), respectively. The second repository (1092) is dispensed to the wheel (460) prior to the dispensing of the first repository (992) to fabricate the electric power generation material (466) with the material dispensed from the first repository (992) being positioned over the material dispensed from the second repository (1092). The nano-fluid (302) is sprayed onto the spacer layer (1006) using the respective electrospray devices (424_B), (424_C), and/or (424_A). In an embodiment, any combination of repositories (412A), (412_b), (412_C), (444), (992), and (1092) is used to fabricate the material (466). Accordingly, the manufacturing system (402) includes the flexibility to fabricate the electric power generation material (466) using two, three, or four repositories of materials.

[0122] Referring to FIG. 11, a flow diagram (1100) is provided illustrating an embodiment of a system (1102) to manufacture electric power generation modules and systems of modules with the (nano-scale) energy harvesting thermionic devices (1190) described herein. The devices (1190) are similar to the arcuate device (690) and the planar device (890). In an embodiment, all of the devices (1190) are arcuate. In an embodiment, all of the devices (1190) are planar. In an embodiment, the devices (1190) are a combination of arcuate and planar. The system (1102) includes a plurality of cell fabrication machines (1104) for the nano-scale energy harvesting devices (1190), where the cell fabrication machines (1104) are similar to the manufacturing systems (402) shown and described in FIG. 4. Ten machines (1104) are shown; however, this quantity is not limiting. The system (1102) is scalable to accommodate from a minimum of one machine (1104) up to multiple thousands of machines (1104). In an embodiment, each machine (1104) has an area footprint of approximately 0.5 m by 1.5 m to about 1.0 m by 2. 5m. The devices (1190) are transported from the machines (1104) to a cell manufacturing station (1106) by a first transport system (1108). In an embodiment, a single transport device (1108) transports the devices (1190) individually to the cell manufacturing station (1106) as they are manufactured by the machines (1104). In an embodiment, the first transport system (1108) is synchronized with the machines (1104) to transport a plurality of devices (1190) simultaneously or near- simultaneously, with the quantity of devices subject to transport being configurable. In an embodiment, the first transport system (1108) transfers the devices (1190) from a storage station (not shown) to the cell manufacturing station (1106). Accordingly, the first transport system (1108) transports the devices (1190) to a station (1106) for final manufacturing of a cell (described further herein).

[0123] The cell manufacturing station (1106) includes a plurality of devices to complete the manufacturing of a cell from the devices (1190). In an embodiment, the station (1106) includes a plurality of insertion devices (1110). The insertion devices (1110) insert the structural members, e.g., for the arcuate devices (690), the structural member (624) is inserted into the axial aperture (618). A planar structural member is inserted into the axial aperture (818) for the planar devices (890). In an embodiment, the station (1106) includes a plurality of sealing devices (1112). The sealing devices apply the sealant (744) to the seam (742) and the sealant (746) to the base areas (720) and (722) for the cylindrical device (790). Similarly, a sealant is applied to the seam (842) and base areas (820) and (822) of the planar device (890). The sealants are applied to the devices (1190) after insertion of the associated structural members to provide for effective isolation of the internals of the devices (1190) from external environmental hazards. In an embodiment, each insertion device (1110) and each sealing device (1112) operate individually as the transport system (1108) delivers a device (1190). In an embodiment, the cell manufacturing station (1106) is synchronized with the transport system (1106) to transport a plurality of the devices (1190) simultaneously or near-simultaneously, with the quantity of the devices (1190) subject to transport being configurable. In an embodiment, the insertion devices (1110) and the sealing devices (1112) are integrated into the cell fabrication machines (1104). Once the structural member is inserted in the device (1190), and the device (1190) is sealed, the device (1190) has been fully manufactured into a power generation nano-cell (1114) ( e.g ., see (790) in FIG. 7), where each cell (1114) is a self-contained electric power generation device. In an embodiment, the devices (1190) are referred to as a partially formed cell. In an embodiment, the severed portions of the fabricated electric power generation material (466) that are used to manufacture the electric power harvesting devices (1190) are referred to as partially formed cells. Accordingly, each device (1190) manufactured by the machines (1104) is fully manufactured into a cell (1114) by the cell manufacturing station (1106).

[0124] The system (1102) includes a second transport system (1116) that transports the cells (1114) to a first assembly and test station (1118). The second transport system (1116) is similar to the first transport system (1108). The first assembly and test station (1118) receives module housings and cell electrical interconnects (1120) from a warehouse to prepare a nano scale electric power generation module (not shown) for receipt of the cells (1114). In an embodiment, a one kilowatt (kw) module, where 1 kw is non-limiting, receives approximately a plurality of cells (1114), where each cell (1114) is capable of generating approximately 6.6 watts. The station (1118) also includes a test device (not shown) that tests the cells (1114) in the module either in combination or individually. In an embodiment, once the 1 kW modules are assembled and tested, the 1 kw modules are subjected to a final station (1122) for final testing, certification, labeling as a finished good, and shipping. In an embodiment, the 1 kw modules are transported to a second assembly and test station (1124) that is similar to the first station (1118). For example, ten 1 kw modules are received by a lOkw module (not shown), where the quantity of modules and energy output are non-limiting values. In an embodiment, once the modules are assembled and tested, the modules are transported to the final station (1122). In an embodiment, the modules are transported to a third assembly and test station (1126) that is similar to the first and second stations (1118) and (1124), respectively. In an embodiment, ten 10 kw modules are received by a 100 kw module (not shown), where 10 modules and 100 kw are non-limiting values. In an embodiment, once the 100 kw modules are assembled and tested, the 100 kw modules are transported to the final station (1122). In an embodiment, the 100 kw modules are transported to a fourth assembly and test station (1128) that is similar to the first, second, and third stations (1118), (1124), and (1126), respectively. In an embodiment, ten 100 kw modules are received by a 1 megawatt (MW) system (not shown), where 10 modules and 1 MW are non limiting values. In an embodiment, once the 1 MW systems are assembled and tested, the 1 MW systems are transported to the final station (1122). The assignment of the term “modules” to the devices in the kw range and “system” to devices in the MW range should not be considered limiting. In an embodiment, systems in the kw range and modules in the MW range are envisioned. The process of assembling power systems with the assembled modules is scalable up to the gigawatt range. Accordingly, the system (1102) is scalable to manufacture electric power generation systems of any size and capacity from the cells (1114) manufactured as described herein.

[0125] A control system (1130) is operably coupled to the cell fabrication machines (1104), the first transport system (1108), the insertion devices (1110), the sealing devices (1112), the second transport system (1116), the assembly and testing stations (1118), (1124), (1126), and (1128), and the final station (1122). In an embodiment, the control system (1130) is similar to the control system (410). In an embodiment, the control system (410) is embedded within the control system (1130). In an embodiment, the control system (1130) is embedded within the control system (410). In an embodiment, the control system (410) and (1130) are separate systems that communicate with each other. The control system (1130) coordinates the transport of the devices (1190) through the process of being manufactured into cells (1114) and the subsequent assembly of the cells (1114) into power modules in the kilowatt range and the power modules into power systems in the megawatt through gigawatt ranges. Accordingly, the system (1102) includes the control system (1130) to regulate the processes described herein for FIG. 11 from the cell fabrication machines (1104) to the final station (1122).

[0126] Referring to FIG. 12, a schematic view (1200) is provided to illustrate an embodiment of a manufacturing system (1202) for the nano-scale energy harvesting thermionic devices (100), (690), (790), and (890). The system (1202) includes a plurality of cell fabrication machines (1204).Ten machines (1204) are shown; however, this number is not limiting. The system (1202) is scalable to accommodate one machine (1204) up to a multiple of thousands of machines (1204).

[0127] Each machine (1204) includes a collector electrode dispenser (1206), an emitter electrode dispenser (1208), and a spacer dispenser (1210), where dispensers (1206), (1208), and (1210) are similar to dispensers (404A), (404_B), and (404c), respectively. Each machine (1204) also includes a plurality of electrospray devices (not shown FIG. 12) similar to the electrospray devices (424A) and (424_B) to deposit a patterned coating of, for example, CS2O (134) and (164) on the emitter and collector electrodes (102) and (104), respectively, prior to the spacer material (106) contacting the electrodes (102) and (104). An electrospray apparatus (1212) is positioned to spray the nano-fluid (302) onto one or more of the electrodes (102) and (104) and the spacer (106) prior to winding the assembled materials into a partially formed product.

[0128] A transport device (1214) transports the wound, partially formed object to a vacuum chamber (1216) where infusion of the nano-fluid (302) into the apertures (206) of the spacer (106) is achieved. In an embodiment, the system (1202) includes a nano-fluid delivery system (1220) that includes a nano-fluid reservoir (1222) coupled in fluid communication with the nano-fluid electrospray apparatus (1212) through a plurality of fluid conduits (1224).

[0129] Upon completion of the nano-fluid infusion, a partial cell (1230), similar to the partial cell (1190), is transported through a first transport system (1232) that is similar to the first transport system (1108), to an insertion device (1234) and a sealing device (1236), that is similar to insertion devices (1110) and sealing devices (1112), respectively. The finished cell (1240) is transported to a suite of assembly and testing stations (1242) by a second transport system (1244) that is similar to the second transport system (1116). The assembly and testing stations (1242) are similar to the assembly and testing stations (1118), (1124), (1126), and (1128), and the final station (1122). Accordingly, nano-fluid (302) is infused to manufacture the cells (1230).

[0130] As described herein, the present disclosure is directed generally to manufacturing an energy source, and more particularly, is directed to manufacturing energy harvesting thermionic devices, especially those that are nano-scale and/or contain nano-scale component(s). Specific materials are either provided or fabricated and are joined to manufacture the energy harvesting thermionic devices. In exemplary embodiments, the materials include electrodes fabricated from two different materials that are at least partially coated with a material such as CS O to provide the two electrodes with different work function values. In an exemplary embodiment, the emitter electrode and a collector electrode are fabricated, where the emitter electrode had a larger work function value than the collector electrode. A separation material is positioned between the two electrodes. In an exemplary embodiment, apertures within the separation material are filled with a nano-fluid that includes nanoparticle clusters with greater work function values than either of the two electrodes. This arrangement of materials induces electron current flow from the emitter electrode, through the nano-fluid, to the collector electrode. The mechanisms for the electron transfer through the nano-fluid include Brownian motion of the nanoparticle clusters and electron tunneling across distances. In an embodiment, the electron tunneling distances are less than 20 nm. The design of exemplary embodiments of these devices enables ambient energy extraction at low temperatures (including room temperature). The devices described herein initiate electron flow due to differences in Fermi levels of the electrodes without the need for an initial temperature differential or thermal gradient. The electron current can be increased through the addition of heat energy to the emitter electrode and electrically connecting the energy harvesting thermionic device to an external circuit with loads thereon.

[0131] In exemplary embodiments, the systems to manufacture the nano-scale energy harvesting devices include a plurality of dispensers that receive repositories of the materials used to manufacture the devices. The materials on the repositories are dispensed toward a center wheel, where the materials are positioned to contact each other. In embodiments, for those electrode materials that do not arrive from the associated vendors with the CS O (or other) coatings thereon, each associated dispenser for the electrodes includes electrospray devices to spray the CS O (or other) coatings onto the electrodes. In embodiments, for those electrode materials that are provided with the CS O (or other) coatings thereon, the electrospray devices are idled or set to an idle position or setting. In exemplary embodiments, the separation materials receive a nano-fluid from one or a plurality of electrospray devices positioned proximate to the associated dispenser. The distances between the materials dispensed from the repositories and the electrospray devices may be determined for each material to optimize precise positioning of the sprayed materials on the unrolled materials. Also, the drying distances for the electrode sprays may be determined to optimize drying on the unrolled electrode materials.

[0132] The manufacturing systems described herein are flexible with respect to accepting varying repositories of materials. In general, the devices include a plurality of layers of different materials that are taken from a respective material repository. In an embodiment, each of the materials for the layers may be assigned a particular dispenser. Also, the repositories may include more than one layer of material such that as few as two repositories may be used to manufacture the devices. In addition, the separation material ( e.g ., the spacer) may be sprayed onto the electrodes rather than inserted between the electrodes.

[0133] The manufacturing systems described herein are also flexible with respect to the devices manufactured therefrom. In embodiments, the product resulting from the dispensers and the center wheel is the material to manufacture the devices is in the form of a web, e.g., nano-web, with four layers. The nano-web may be severed into planar pieces that are immediately transported to a winding device to produce an arcuate- shaped product with the layers defining substantially concentric, cylindrical spirals. The severed portions may be transported to a manufacturing device that will produce a planar product with concentric, quasi-rectangular spirals. The severed sections of the nano- web may be transported to a storage area for future device manufacturing. Regardless of whether the products are arcuate or planar, in embodiments the products receive final manufacturing including insertion of heat removal and electrically conductive materials into central apertures formed by the manufacturing process. In exemplary embodiments, the products are sealed to protect the internal aspects of the products which are now cells. The cells can be grouped in power generation assemblies that are modular in nature or are larger generation systems.

[0134] The energy harvesting thermionic devices, including nano-scale devices, described herein are scalable across a large number of power generation requirements. The devices may be designed for applications requiring electric power in the milliwatts (mW), watts (W), kilowatts (kW), and megawatts (MW) ranges. Examples of devices for the mW range include, but are not limited to, those devices associated with the Internet of Things (IoT) (home appliances, vehicles (communication only)), handheld portable electronic devices ( e.g ., mobile phones, medical devices, tablets), and embedded systems (e.g., RFIDs and wearables). Examples of devices for the watts range include, but are not limited to, handheld sensors, networks, robotic devices, cordless tools, drones, appliances, toys, vehicles, utility lighting, and edge computing. Examples of devices in the kW range include, but are not limited to, residential off-grid devices (rather than backup fossil fuel generators), resilient/sustainable homes, portable generators, electric and silent transportation (including water-faring), and spacecraft. Examples of devices in the MW range include, but are not limited to, industrial/data center/institutional off-grid devices (e.g., uninterruptible power supplies), resilient complexes, urban centers, commercial and military aircraft, flying cars, and railway/locomotive/trucking/shipboard transportation. Accordingly, substantially any power demand in any situation can be met with the devices disclosed herein.

[0135] Aspects of the present embodiments are described herein with reference to one or more of flowchart illustrations and/or block diagrams of methods and apparatus (systems) according to the embodiments.

[0136] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term “and/or” means either or both (or any combination or all of the terms or expressed referred to). It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[0137] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present embodiments has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the embodiments in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the embodiments. The embodiments were chosen and described in order to best explain the principles of the embodiments and the practical application, and to enable others of ordinary skill in the art to understand the embodiments for various embodiments with various modifications as are suited to the particular use contemplated. The implementation of the manufacturing systems of the energy harvesting thermionic devices, including nano-scale devices, facilitates manufacturing the devices on a scale from individual devices to a factory- level scale to produce thousands of devices. Accordingly, the manufacturing systems for the energy harvesting thermionic devices, including nano-scale devices, and the associated embodiments as shown and described in FIGS. 1-12, provide for producing energy harvesting thermionic devices across a wide range of energy consumption requirements.

[0138] It will be appreciated that, although specific embodiments have been described herein for purposes of illustration, various modifications may be made without departing from the spirit and scope of the embodiments. In particular, the manufacturing systems for the (nano-scale) energy harvesting thermionic devices are shown as configured to manufacture these devices with a predetermined set of conditions with respect to the materials used. Alternatively, the manufacturing systems may be configured to manufacture these devices under a variety of conditions with respect to the materials used. Accordingly, the scope of protection of the embodiment(s) is limited only by the following claims and their equivalents.

Claims

CLAIMS What is claimed is:

1. A system comprising: at least one first dispenser configured to dispense a first material and a separation material, the first material having a first work function value; a second dispenser configured to dispense a second material, the second material having a second work function value, the second work function value being different from the first work function value; at least one first device configured to deposit a fluid within at least a portion of the separation material, the fluid having a third work function value, the third work function value being different from the first and second work function values; and a guide assembly operably coupled to the at least one first dispenser and the second dispenser, the guide assembly configured to transport the first and second materials, the positioned separation material, and the fluid to a joint proximal position and form a fabricated product.

2. The system of claim 1, wherein the at least one first dispenser comprises the first dispenser and a third dispenser, wherein: the third dispenser is configured to deposit the separation material between the first material and the second material; the at least one first device is positioned proximal to the third dispenser to deposit the fluid within at least the portion of the separation material dispensed from the third dispenser; and the guide assembly is operably coupled to the first, second, and third dispensers.

3. The system of claim 2, further comprising a fourth dispenser to deposit a casing material over a least a portion of the first material or the second material.

4. The system of claim 2, further comprising a receiver configured to receive the fabricated product.

5. The system of claim 2, wherein the guide assembly comprises: at least one first guide in operable communication with the first dispenser; at least one second guide in operable communication with the second dispenser; and a wheel operatively coupled to the first and second guides.

6. The system of claim 5, wherein the guide assembly further comprises: at least one third guide in operable communication with the third dispenser and the wheel; and at least one fourth guide in operable communication with the wheel and a receiver to receive the fabricated product.

7. The system of claim 4, wherein the guide assembly and a receiver are in a serial relationship, the receiver comprising a cutting device positioned to sever the fabricated product into one or more severed portions having one or more predetermined characteristics.

8. The system of claim 7, wherein the receiver further comprises a winding device operably coupled to the cutting device, the winding device configured to wind one or more of the severed portions into an arcuate object.

9. The system of claim 7, wherein the receiver further comprising a winding device operably coupled to the cutting device, the winding device configured to wind the one or more severed portions into an arcuate object having a cylindrical structure with a radius and an axial centerline orthogonal to the radius.

10. The system of claim 9, wherein the winding device is configured to form the arcuate object with a conduit coincident with the axial centerline.

11. The system of claim 10, further comprising an insertion device to insert a heat transfer member at least partially into the conduit.

12. The system of claim 10, further comprising an insertion device to insert an electrical conductor at least partially into the conduit.

13. The system of claim 7, further comprising a sealing device to deposit a sealing material on one or more surfaces of the one or more severed portions.

14. The system of claim 7, further comprising the cutting device configured to sever the fabricated product into a plurality of planar portions.

15. The system of claim 2, wherein the first material is dispensed from a first repository, the second material is dispensed from a second repository, and the separation material is dispensed from a third repository, the first, second, and third repositories being separately controlled repositories.

16. The system of claim 2, wherein the third dispenser is at least one electrospray device configured to spray the separation material onto the first electrode and/or the second electrode.

17. The system of claim 16, wherein the third dispenser and the guide assembly are arranged relative to one another to provide a first distance extending between the dispensed separation material and the joint proximal position.

18. The system of claim 2, further comprising: a fifth material extending over at least a portion of the first material, wherein the first material and the fifth material define a first electrode; and a sixth material extending over at least a portion of the second material, wherein the second material and the sixth material define a second electrode.

19. The system of claim 2, further comprising: at least one first electrospray device positioned proximal to the first dispenser, the first electrospray device configured to deposit at least one first electrospray material over at least a portion of the first material dispensed from the first dispenser to fabricate a first electrode comprising the first material and the first electrospray material, the fabricated first electrode having a fourth work function value, the fourth work function value being different from the first, second, and third work function values; and at least one second electrospray device positioned proximal to the second dispenser, the second electrospray device configured to deposit at least one second electrospray material over at least a portion of the second material dispensed from the second dispenser to fabricate a second electrode comprising the second material and the second electrospray material, the fabricated second electrode having a fifth work function value, the fifth work function value being different from the first, second, third, and fourth work function values.

20. The system of claim 19, further comprising: a first distance extending between the dispensed first material and the first electrospray device; and a second distance extending between the dispensed second material and the second electro spray device.

21. The system of claim 20, further comprising: a third distance extending between the first electrospray device and a position proximate to the forming of the joint proximal position, wherein the third distance is a first drying region of the sprayed first material; and a fourth distance positioned between the second electrospray device and the position proximate to the forming of the joint proximal position, wherein the fourth distance is a second drying region of the sprayed second material.

22. The system of claim 20, further comprising: a first sensor proximate the first device to monitor the deposition of the fluid; a second sensor proximate the first electrospray device to monitor the deposition of the first electrospray material; and a third sensor proximate the second electrospray device to monitor the deposition of the second electrospray material.

23. The system of claim 22, wherein the first, second, and third sensors are cameras.

24. The system of claim 7, wherein the cutting head is configured to sever the fabricated product into a severed portion that at least partially forms a cell.

25. The system of claim 7, wherein the cutting heat is configured to sever the fabricated product into a severed portion that partially forms an arcuate cell or a planar cell.

26. The system of claim 25, wherein the first, second, and third dispensers, the guide assembly, and the cutting device define a first cell fabrication machine.

27. The system of claim 26, further comprising a plurality of cell fabrication machines.

28. The system of claim 27, further comprising a cell transport device to selectively transport a cell from the plurality of cell fabrication machines to an assembly area for testing of a plurality of the cells and/or inserting of the cells into a nano-scale electric power generation module.

29. The system of claim 28, further comprising a module assembly device to selectively insert one or more of the cells into the nano-scale electric power generation module.

30. The system of claim 29, further comprising a system manufacturing device to selectively insert one or more of the nano-scale electric power generation modules into a nano-scale electric power generation system.

31. The system of claim 30, further comprising a control system to regulate operation of the plurality of cell fabrication machines, the cell transport device, the module assembly device, and the system manufacturing device.

32. The system of claim 2, wherein first device positioned proximal to the third dispenser is an electro-spray device, and the deposited fluid is a nano-fluid.

33. A method comprising: providing the system of claim 2; dispensing the first material from the first dispenser, the first material having the first work function value; dispensing the second material from the second dispenser, the second material having the second work function value; depositing the separation material from the third dispenser between the first and second materials; depositing a fluid from the at least one first device positioned proximal to the third dispenser within at least a portion of the separation material dispensed from the third dispenser, the third work function value of the fluid being different than the first and second work function values; and transporting the first and second materials, the separation material, and the fluid using the guide assembly to a joint proximal position and forming a fabricated product.

34. The system of claim 1, wherein: the first dispenser is configured to dispense a first component, the first component including: a first electrode comprised of the first material, the first electrode having the first work function value; and the separation material positioned in at least partial communication with the first electrode; the second dispenser is configured to dispense a second component, the second component including a second electrode comprised of the second material, the second electrode having the second work function value; the at least one device is positioned proximal to the first dispenser, the device configured to deposit the fluid within at least a portion of the separation material dispensed from the first dispenser, at least a portion of particles within the fluid having the third work function value being different from the first and second work function values; and the guide assembly is operably coupled to the first and second dispensers, the guide assembly configured to transport the first and second components to the joint proximal position to form the fabricated product including the first and second components and the fluid.

35. The system of claim 34, wherein the second component further includes a casing material positioned in at least partial communication with the second electrode.

36. The system of claim 35, further comprising: a first repository for providing the first component to the first dispenser for dispensing; and a second repository for providing second component to the second dispenser for dispensing, the first and second repositories being separately controlled repositories.

37. The system of claim 34, wherein the at least one device positioned proximal to the first dispenser is an electro-spray device, and the deposited fluid is a nano-fluid.

38. A method comprising: providing the system of claim 34; dispensing the first component from the first dispenser, the first component comprising the first electrode having the first work function value and the separation material positioned in at least partial communication with the first electrode; dispensing the second component from the second dispenser, the second component including the second electrode having the second work function value that is different than the first work function value; depositing the fluid from the at least one device positioned proximal to the first dispenser to within the at least a portion of the dispensed separation material, at least the portion of particles within the fluid having the third work function value that is different than the first and second work function values; and transporting the first and second components using the guide assembly to the joint proximal position to form the fabricated product including the first and second components and the fluid.

39. A system comprising: a first dispenser configured to dispense a first material, the first material having a first work function value; a second dispenser configured to dispense a second material, the second material having a second work function value, the second work function value being different from the first work function value; a first device positioned proximal to the first dispenser, the first device configured to deposit at least one first electrospray material over at least a portion of the first material dispensed from the first dispenser to fabricate a first electrode material comprising the first material and the deposit of the first electrospray material, the fabricated first electrode material having a third work function value; a second device positioned proximal to the second dispenser, the second device configured to deposit at least one second electrospray material over at least a portion of the second material dispensed from the second dispenser to fabricate a second electrode material comprising the second material and the deposit of the second electrospray material, the fabricated second electrode material having a fourth work function value; a guide assembly operably coupled to the first and second dispensers, the guide assembly configured to transport the first and second electrode materials to a joint proximal position, including the guide assembly to position an opening between the first and second electrode materials; a third dispenser configured to deposit a separation material into the positioned opening; and the system configured to fabricate a product including the first and second electrode materials and the positioned separation material.

40. The system of claim 39, further comprising a vacuum chamber to infuse the fluid into the fabricated product.

41. The system of claim 40, wherein: the third work function value is less than the first work function value; the fourth work function value is less than the second work function value, and the third work function value is less than the fourth work function value; and the fluid having a fifth work function value greater than the third and fourth work function values, wherein the first and second electrode materials and the fluid cooperate to generate electric power as a function of the associated work functions.

42. The system of claim 40, wherein the first and second electrode materials and the positioned separation material at least partially define a first partial product, the system further comprising a transport device to selectively transport the first partial product from a first location to the vacuum chamber.

43. The system of claim 40, further comprising a fluid delivery system comprising: at least one fluid reservoir; and at least one fluid delivery conduit configured to couple the fluid reservoir in fluid communication with the vacuum chamber.

44. The system of claim 39, wherein first device positioned proximal to the first dispenser is a first electro-spray device, and the second device positioned proximal to the second dispense is a second electro-spray device.

45. The system of claim 38, wherein the fluid is a nano-fluid.

46. A method comprising: providing the system of claim 39; dispensing the first material having the first work function value from the first dispenser; dispensing a second material having the second work function value that differs from the first work function value from the second dispenser; depositing the at least one first electrospray material from the first device onto the at least a portion of the first material dispensed from the first dispenser to fabricate the first electrode material, the fabricated first electrode material comprising the first material and the deposit of the first electrospray material, the fabricated first electrode material having the third work function value; depositing the at least one second electrospray material from the second device onto the at least a portion of the second material dispensed from the second dispenser to fabricate the second electrode material, the fabricated second electrode material comprising the second material and the deposit of the second electrospray material, the fabricated second electrode material having the fourth work function value; transporting the first and second electrode materials using the guide assembly to the joint proximal position, and positioning the opening between the first and second electrode materials; depositing the separation material from the third dispenser into the positioned opening; and fabricating the product including the first and second electrode materials and the positioned separation material.