RU2588036C2 - Structures made using nanotechnology for porous electrochemical capacitors - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering and microelectronics, specifically to devices for energy storage, in which are made porous electrodes for electrochemical capacitors with a highly developed porous surface formed with use of nanotechnology. Disclosed are versions of device for energy storage, as well as a method of forming device and porous electrodes. In an embodiment, energy storage device includes a porous structure formed by a plurality of main channels within conductive structure in direction of crystal plane, each of main channel has an opening at main surface of crystal, and each of main channel is held in an electrically conductive structure at an acute angle to main surface of crystal. In an embodiment, energy storage device includes a porous structure comprising a matrix of V-shaped grooves, pyramidal indentations.

EFFECT: high capacity and reliability of energy storage devices.

27 cl, 27 dwg

Description

FIELD OF THE INVENTION

The disclosed embodiments of the invention generally relate to energy storage devices, and more specifically, relate to methods for forming porous electrodes with a highly developed surface.

State of the art

Modern society depends on the easy availability of energy. As energy demand increases, devices capable of efficiently storing energy are becoming increasingly important. As a result, energy storage devices, including devices such as batteries, capacitors, electrochemical capacitors (ECs), including ionistors and electric double layer capacitors (EDLCs), also known as supercapacitors, among other names, hybrid electrochemical capacitors (ECs), and similar devices widely used in the electronic field of technology and beyond. In particular, capacitors are widely used for applications in a wide range from electrical circuits and power supply to voltage regulation and replacement of electric batteries. Electrochemical capacitors are characterized by high energy storage capacity, as well as other desirable characteristics, including high energy density, small size, low weight, and thus become promising candidates for use in some applications for energy storage.

WO 2011/123135 discloses three-dimensional structures for forming electrochemical capacitors with a high energy density. Some of the disclosed embodiments use a wet etching process to etch deep pores in a silicon structure, and the pores are filled with an electrolyte or a dielectric material with high dielectric constant and / or a thin conductive film in combination with an electrolyte.

Brief Description of the Drawings

The disclosed embodiments of the invention will be more apparent after reading the following detailed description made in conjunction with the accompanying figures in the drawings, in which:

FIG. 1 is a sectional side view illustrating an energy storage device according to an embodiment of the invention.

FIG. 2 is a side sectional view illustrating an electric double layer inside a porous structure of an energy storage device in accordance with an embodiment of the invention.

FIG. 3 is a cross-sectional side view illustrating a porous structure formed on a silicon surface (1011) in accordance with an embodiment of the invention.

FIG. 4 is a sectional side view illustrating an energy storage device according to an embodiment of the invention.

FIG. 5 is a close-up side view of a sectional view illustrating a main channel in accordance with an embodiment of the invention.

FIG. 6 is a cross-sectional side view illustrating an image of a porous structure formed in a silicon surface (322) in accordance with an embodiment of the invention.

FIG. 7 is a sectional side view illustrating a porous structure formed in a silicon surface (111) according to an embodiment of the invention.

FIG. 8 is a process flow diagram illustrating a method of forming a porous electrode in accordance with an embodiment of the invention.

FIG. 9-10 are schematic sectional side views illustrating a porous structure in accordance with embodiments of the invention.

FIG. 11 is a process flow diagram illustrating a method of forming a porous electrode in accordance with an embodiment of the invention.

FIG. 12-13 are schematic sectional side views illustrating a porous structure in accordance with embodiments of the invention; as well as a method for electrochemical etching of a porous structure in accordance with an embodiment of the invention.

FIG. 14 is a process flow diagram illustrating a method of forming a porous electrode with a matrix of V-shaped grooves or pyramidal recesses, in accordance with an embodiment of the invention.

FIG. 15 is a plan view illustrating lines of a pattern of a matrix formed over a substrate in accordance with an embodiment of the invention.

FIG. 16 is a plan view illustrating a matrix of V-grooves and recesses formed in a substrate in accordance with an embodiment of the invention.

FIG. 17 is a plan view illustrating lines of a pattern of a matrix formed over a substrate in accordance with an embodiment of the invention.

FIG. 18 is a plan view illustrating a matrix of pyramidal recesses formed in a substrate in accordance with an embodiment of the invention.

FIG. 19 is a sectional side view illustrating a porous structure of an energy storage device according to an embodiment of the invention.

FIG. 20 is a sectional side view illustrating a porous structure of an energy storage device according to an embodiment of the invention.

FIG. 21 is a cross-sectional side view illustrating an energy storage device according to an embodiment of the invention.

FIG. 22 is a flowchart illustrating a method of forming an energy storage device according to an embodiment of the invention.

FIG. 23A-23B are cross-sectional side views illustrating an energy storage device in accordance with embodiments of the invention.

FIG. 24 is a process flow diagram illustrating a method of forming an energy storage device according to an embodiment of the invention.

FIG. 25 is a cross-sectional side view illustrating a porous structure released from a conductive substrate in an electrochemical etching bath in accordance with an embodiment of the invention.

FIG. 26 is a block diagram illustrating a mobile electronic device in accordance with an embodiment of the invention.

FIG. 27 is a block diagram illustrating a microelectronic device in accordance with an embodiment of the invention.

The implementation of the invention

For simplicity and clarity, the figures illustrate the general construction principle, and descriptions and details of well-known features and technologies may be omitted to avoid unnecessarily introducing ambiguity into the discussion of the described embodiments of the invention. In addition, elements in the drawings are not necessarily shown to scale. For example, the dimensions of some elements in the figures may be increased in relation to other elements to help improve understanding of embodiments of the present invention. Certain shapes can be shown in an idealized way in order to help a better understanding, for example, in cases where structures are depicted having straight lines, sharp angles, and / or parallel planes, or similar parameters that would probably be significantly less symmetrical in real conditions and orderly. The same numeric positions in different figures indicate the same elements, while similar digital positions may, but not necessarily, indicate similar elements.

The terms “first”, “second”, “third”, “fourth” and similar terms in the description and in the claims, if any, are used to distinguish between similar elements, and not necessarily to describe a special sequence order or chronological order. It should be understood that the terms used in this way are interchangeable in certain circumstances, thus the embodiments described herein, for example, have the ability to perform operations in sequences that differ from those illustrated or otherwise described herein. Similarly, if the method is described here as containing a sequence of steps, then the order of such steps presented here is not necessarily the only order in which such steps can be performed, while certain steps from the established steps may possibly be skipped and / or certain other steps not described here may possibly be added to the method. In addition, the terms “comprise,” “include,” “have,” and any variations thereof, are intended to include a non-exclusive addition, such as a process, method, product, or device, that contain a list of elements, wherein it is not necessarily limited to these elements, but may include other elements that are not specifically listed or not necessarily inherent in such a process, method, product, or device.

The terms “left”, “right”, “front”, “rear”, “upper”, “lower”, “above”, “under” and similar terms in the description and in the claims, if any, are used for descriptive purposes and are not necessarily used to describe permanent relative positions, unless otherwise indicated otherwise, either specifically or in context. It should be understood that the terms used in this way are interchangeable in certain circumstances, thus, the embodiments of the invention described herein, for example, have the ability to perform operations in different orientations compared to those illustrated or otherwise described here. The term “connected”, as used here, is defined as connected directly or indirectly by electrical or non-electrical means. The objects described here, as being “adjacent” to each other, can be in physical contact with each other, in close proximity to each other, or in the same general area or sphere, both in relation to each other and appropriate for the context in which the phrase is used. The presence of the phrase “in one embodiment of the invention” here does not necessarily always refer to the same embodiment of the invention.

In one aspect, embodiments of the invention describe an energy storage device and a method of forming an energy storage device in which the surface area of a porous structure containing a plurality of main channels within the electrically conductive structure is increased by forming the main channels along the direction of the crystal plane in the electrically conductive structure. In an embodiment of the invention, each of the main channels extends in an electrically conductive structure along the direction of the plane of the crystal, oriented at an acute angle to the main surface of the porous structure. In an embodiment of the invention, the side channels extend from the side surface of each of the main channels in the electrically conductive structure, for example, along the direction of the etching current in the bath for electrochemical etching.

In one aspect, embodiments of the invention describe an energy storage device and a method of forming an energy storage device with a reduced diffusion path length. In an embodiment of the invention, the energy storage device includes a porous structure comprising a plurality of main channels that are linearly conical. For example, linearly conical main channels can be formed by changing the etching current during electrochemical etching in a nonlinear manner. In another embodiment of the invention, the etching current during electrochemical etching can vary non-linearly to form reservoirs in a plurality of main channels. Such structures can reduce the diffusion path length for ions, which reduces the diffusion time constant and makes it possible for such energy storage devices to operate at a higher power.

In one aspect, embodiments of the invention describe an energy storage device and a method of forming an energy storage device with an enhanced porous structure. In an embodiment of the invention, the energy storage device includes a porous structure comprising a plurality of main channels, which include a primary surface shape and a secondary surface shape superimposed on the primary surface shape. In an embodiment of the invention, a change in the secondary etching current during electrochemical etching is superimposed on a change in the primary etching current during electrochemical etching. For example, a change in the secondary etching current during electrochemical etching can be a linear addition of a sinusoidal function. Such a sinusoidal change can eliminate sharp changes in porosity, which reduces stress concentration and strengthens the porous structure.

In one aspect, embodiments of the invention describe an energy storage device and a method of forming an energy storage device in which the electrochemical etching conditions are controlled to reduce pore size, thereby increasing the porous surface area and electric capacity of the energy storage device. In an embodiment of the invention, the electrochemical pickling bath operates at about room or lower temperature. In an embodiment of the invention, the electrochemical pickling bath contains a concentration of hydrofluoric acid (HF): alcohol in a ratio of 2: 1, or with a higher concentration of HF. In an embodiment of the invention, the alcohol may be either isopropyl or ethyl alcohol.

In one aspect, embodiments of the invention describe an energy storage device and a method of forming an energy storage device with reduced effective series resistance by increasing the surface area between two electrodes of the energy storage device. In an embodiment of the invention, the surface area increases due to the formation of V-grooves or pyramidal recesses in the main surface of the porous structure in one or both structures of the porous electrode.

In one aspect, embodiments of the invention describe a method using a hybrid material to form an energy storage device. In an embodiment of the invention, the first porous electrode is formed by electrochemical etching of the porous structure in the electrically conductive substrate. In an embodiment of the invention, the first porous electrode may integrate with another circuit in an electrically conductive substrate. The separator and the second porous electrode can then be deposited on the first porous electrode using thin film deposition technology.

In one aspect, embodiments of the invention describe an energy storage device and a method of forming an energy storage device using an electrochemical etching mode to obtain free-standing porous structures. In an embodiment of the invention, a porous structure is formed in an electrically conductive substrate immersed in a bath for electrochemical etching, followed by an increase in current for electrochemical etching to release the porous structure from the electrically conductive substrate. The released porous structure is then connected to the separator layer and the second porous structure to form an energy storage device.

Although much of this discussion will focus on electrochemical capacitors (including ionistors and double-layer electric capacitors), the detailed designation “energy storage device” includes in addition to electrochemical capacitors (ECs), hybrid ECs also batteries, fuel cells and similar devices that save energy. Energy storage devices in accordance with embodiments of the invention can be used for a wide variety of applications, including automobiles, buses, trains, airplanes, other vehicles, household energy storage devices, energy storage devices generated by solar or wind energy generators (especially energy absorption devices), and many others.

Electrochemical capacitors operate in accordance with principles similar to those used for traditional parallel plate capacitors, but they are subject to certain important differences. One significant difference is the charge separation mechanism. For one important class of electrochemical capacitors, it usually takes the form of the so-called electric double layer, or EDL, to a greater extent than a dielectric or traditional capacitor. An electric double layer (EDL) is created by the electrochemical behavior of ions on the interface between an electrode with a highly developed surface and an electrolyte, and the resulting effective charge separation, despite the fact that the layers are so close to each other. (The distances of physical separation are of the order of a single nanometer). Thus, it can be considered that a typical electric double layer capacitor (EDLC) stores charge in the electric double layer. Each EDL layer is electrically conductive, but the properties of this double layer prevent current from flowing through the boundary between them. (EDL will be further discussed below in conjunction with FIG. 2).

It is also true for traditional capacitors that the capacitance in an electric two-layer capacitor is proportional to the surface area of the electrodes and inversely proportional to the separation distance of the charges. Very high capacities can be achieved in an electric two-layer capacitor in part due to the very high surface area inherent in the multichannel porous structure and the separation distance of nanometer-scale charges inherent in the electric double layer, which increase due to the presence of an electrolyte, as explained above. One type of electrolyte that can be used in accordance with embodiments of the invention is an ionic liquid. Another type is an electrolyte including an ion-containing solvent. It is also possible to use organic electrolytes, aqueous electrolytes, and solid state electrolytes.

Another class of electrochemical capacitors is the ionistor, in which, in addition to the capacity of the electric double layer, an additional storage mechanism appears - one of which is Faraday, and not electrostatic in origin - can increase the surface of certain types of electrodes. An additional storage mechanism is usually defined as “electrical pseudo-capacity” and is characterized by a charge storage process, which is similar to the operation of many solid electrode batteries. Two storage mechanisms complement each other, and lead to even greater potential for energy conservation than that which is possible when using only the capacity of the electric double layer. Typically one of these electrodes is covered by an intermediate layer supercapacitors metal oxide such as MnO _2, RuO _2, NiO _x, Nb ₂ O _5, V ₂ O _5, etc., or other materials, which include Mo ₂ N, VN, W ₂ N, W ₂ C (tungsten carbide), Mo ₂ C, VC, a suitable electrically conductive polymer, or similar material. These materials can be used with an electrolyte such as potassium hydroxide (KOH); in this case, when the device is charging, the electrolyte will react with the material and start the reaction of charge movement to where the energy is stored. More precisely, these materials retain a large part of their energy due to a highly reversible surface and electron transfer in the surface layer (for example, redox (Faraday) reactions), which allow higher power than random storage in traditional batteries, due to the fast kinematics of charge and discharge.

It should be understood that ionistors can be created using other electrolytes other than those mentioned above. For example, ionic solvents such as Li ₂ SO ₄ or LiPF ₆ can be used as electrolytes; their use leads to an intercalation reaction, which causes the insertion of isotopes into the surface of the original structure without breaking any bonds. This reaction, like the other electric pseudocapacitance reactions mentioned earlier, results in charge transfer in such a way that it is actually Faraday and is considered as a redox reaction, although it is a redox reaction of a special type.

Hybrid electrochemical capacitors are energy storage devices that combine the characteristic properties of electrochemical capacitors (EC) and batteries. In one example, an electrode coated with a lithium-ion material is combined with an electrochemical capacitor in order to create a device that has a fast exchange and exchange characteristics, like the EU, and a high energy density, like a battery. On the other hand, hybrid ECs, like batteries, have a shorter service life compared to electrochemical capacitors.

FIG. 1 is a side sectional view of an energy storage device 100 in accordance with embodiments of the invention. As illustrated in FIG. , the energy storage device 100 comprises an electrically conductive structure 110 and an electrically conductive structure 120 separated by a spacer 130, which is an electrical insulator and an ionic conductor. The separator 130 prevents physical contact between the electrically conductive structures 110 and 120, in order to prevent electrical short circuit. For example, the spacer 130 may be a permeable membrane or other porous polymer spacer. In general, the separator prevents physical contact between the anode and cathode (which will cause an electrical failure of the device), while at the same time allowing the transfer of ion charge carriers. In addition to polymer separators, several other types of separators are also possible. These include sheets of fibrous sheet material, liquid membranes, polymer electrolytes, solid ionic conductors, and the like. In other embodiments, a separator is optional and may not be used.

At least one of the electrically conductive structures, i.e. 110 or 120, contains a porous structure. As illustrated in FIG. In an embodiment of the invention, both electrically conductive structures comprise an electrically conductive porous structure. In accordance with some embodiments of the invention, the porous structures comprise a plurality of main channels 111 and 121, each of which has an opening in the main surface of the corresponding porous structure. This feature may be the result of the electrochemical etching process described below, used to form a porous structure. For example, a porous structure may be formed inside an electrically conductive material, such as, for example, a conductive material or a semiconductor material. Alternatively, a porous structure may be formed inside an insulating material (eg, alumina) that has been coated with an electrically conductive film (eg, an electrically conductive film using an ALD atomic layer deposition method such as a titanium nitride (TiN) film. In this regard, the materials having better conductive properties are preferred because they have lower effective series resistance (ESR). In the illustrated embodiments, both ele the conductive structures, ie 110 and 120, contain such a porous structure. Accordingly, the conductive structure 110 comprises main channels 111 with holes 112 in the main surface 115 of the corresponding porous structure, and the conductive structure 120 contains main channels 121 with openings 122 in the main surface 125 of the corresponding porous structure In those embodiments of the invention where only one of the electrically conductive structures, i.e. 110 or 120, contains a porous structure with many main channels, there may be another electrically conductive structure, for example, a metal electrode, a polycrystalline silicon structure, carbon, a carbon-based material, a material containing lithium ions, or a pseudocapacitive material.

In an embodiment of the invention, a porous silicon structure can be created by etching an electrically conductive silicon substrate with a mixture of hydrofluoric acid and alcohol in an electrochemical etching bath. However, embodiments of the invention are not limited to porous silicon structures, and embodiments of the invention are not limited to electrochemical etching. Electrochemical etching is described here as one way of forming a porous structure in an electrically conductive structure. In addition to porous silicon, some other materials may also be particularly suitable for energy storage devices in accordance with embodiments of the invention, for example, porous germanium and porous tin. Possible advantages when using porous silicon include compatibility with existing silicon technology. Porous germanium has a similar advantage as a result of the existing technology for this material, and compared with silicon, it has the additional possible advantage that natural oxide (germanium oxide) is soluble in water and therefore easily removed. (The natural oxide that forms on the surface of silicon can trap a charge, which is an undesirable result, especially when the porosity of silicon is greater than about 20 percent). Porous germanium is also well compatible with silicon technology. Possible benefits of using porous tin, which is a zero energy gap material, include increased electrical conductivity with respect to certain other electrically conductive and semiconductor materials. Other materials can also be used to create a porous structure, including silicon carbide, alloys such as an alloy of silicon and germanium, as well as metals such as copper, aluminum, nickel, calcium, tungsten, molybdenum, and manganese.

The energy storage device 100 may optionally include a coating 140, at least in part of the porous structure and at least in some of the main channels 111 and / or main channels 121. In an embodiment of the invention, the coating 140 is a dielectric layer. A dielectric layer may be added in order to further increase the capacity of the energy storage device, or for other reasons, such as, but not limited to, increasing the passivation and wettability of the surface. In an embodiment of the invention, coating 140 is an electrically conductive coating to maintain or increase the electrical conductivity of the porous structure, or it may be useful in reducing the effective series resistance (ESR), thereby improving technical characteristics. For example, a device having a lower ESR is capable of delivering higher power (which can be manifested in terms of greater throttle response, more horsepower, etc.). Conversely, a higher ESR (the state that prevails within a typical battery) limits the amount of available energy, at least in part, due to the fact that a significant part of the energy is wasted on heat.

In FIG. 1 also illustrates electrolyte 150, which causes an electric double layer (EDL). This electrical double layer is shown schematically in FIG. 2. As illustrated in FIG. 2, an EDL 230 was formed inside one of the main channels 111. The EDL 230 is made of two charge layers, one of which is the electric charge of the side walls of the main channel 111 (shown as positive in Fig. 2, but can also be negative), and the other formed due to free electrolyte ions. The EDL 230 electrically isolates the surface, thus providing the charge separation necessary to fulfill the function of a capacitor. The large capacitance, and therefore the potential for energy conservation of electric double-layer capacitors (EDLC) increases due to the small separation (approximately 1 nm) between the electrolyte ions and the surface charge of the electrode. In some embodiments, electrolyte 150 is an organic substance. One type of electrolyte that can be used in accordance with embodiments of the invention is an ionic solution (liquid or solid). Another is an electrolyte (e.g., Li ₂ SO ₄ , L1PF6) including an ion-containing solvent. For example, the electrolyte may be a liquid or solid solution of organic materials such as tetraethylammonium tetrafluoroborate in acetonitrile. Other examples include solutions based on boric acid, sodium tetraborate decahydrate, or weak organic acids. Organic electrolytes and solid state electrolytes are also possible. Electrolyte 150 (as well as other electrolytes described herein) is shown in the drawings using randomly arranged circles. This idea suggests conveying the idea that the electrolyte is a substance (liquid or solid, including gel-like materials) containing free ions. The circles were chosen for convenience, and it is not intended to impose any limitation on the components or qualities, including any limitation on the size, shape, or number of ions.

It should also be noted that images of porous structures in FIG. 1 are substantially idealized, to mention only one example, consisting in the fact that all the main channels 111 and 121 are shown passing in a single direction. In reality, the main channels can have untreated surfaces and can branch in many directions. Exemplary porous structures are depicted in FIG. 3 and FIG. 6-7. Similarly, the surfaces of the main channels 111 in FIG. 2 are illustrated as untreated.

In an embodiment of the invention, the porous structure of the electrically conductive structure 110 and / or 120 comprises a plurality of main channels 111, 121 inside the electrically conductive structure 110, 120, and each of the main channels has an opening 112, 122 on a major surface 115, 125 of a corresponding porous structure, each of the main channels 111, 121 passes in an electrically conductive structure 110, 120 at an acute angle to the main surface 115, 125. Many of the main channels 111, 121 can be oriented along the current transmission line due to etching in the electrically conductive st a structure in the direction of the local current flow during electrochemical etching, or the plurality of main channels 111, 121 can preferably be etched in a crystallographic direction in an electrically conductive structure. In an embodiment of the invention, the main surface 115 is the surface (1011), and each of the main channels 111 extends in the electrically conductive structure 110 along the direction <100> of the crystal plane at an acute angle to the main surface, as shown in the sectional side view of FIG. 3. In an embodiment of the invention, the side channels extend over the side surface of each of the main channels in the porous structure. FIG. 4 is a cross-sectional side view illustrating an energy storage device 100 similar to the device illustrated in FIG. 1, in accordance with embodiments of the invention. As illustrated in FIG. , the porous structures of the electrically conductive structures 110 and / or 120 comprise a plurality of main channels 111, 121, wherein each channel of the plurality of main channels has an opening 112, 122 on a main surface 115, 125 of a corresponding porous structure. In addition, the side channels 117, 127 are formed in the side surface of the main channels 111, 121 and the main surfaces 115,125.

FIG. 5 is a close-up side view of a sectional view illustrating a main channel 111 formed in an electrically conductive structure 110, in accordance with an embodiment of the invention. As illustrated in FIG. 5, the side channels 117 are preferably formed in the side surface 111 B as opposed to the side surface 111 A. In an embodiment of the invention, the preferred formation of the side channels 117 is along the direction of current flow during electrochemical etching. FIG. 6 is a sectional side view illustrating an image of a porous structure formed in a silicon surface (322), in accordance with an embodiment of the invention. As illustrated in FIG. , the main channels 111 extend in the electrically conductive structure 110 along the direction <100> of the crystal plane at an acute angle (322) to the main surface 115 of the porous structure. Side channels 117 are preferably formed in a side surface 111B corresponding to a side surface 111 A. FIG. 7 is a sectional side view illustrating a porous structure formed in a silicon surface (111) according to an embodiment of the invention. As illustrated in FIG. , the main channels 111 extend in the electrically conductive structure 110 along the direction <113> of the crystal plane at an acute angle to the direction (111) of the main surface 115 of the porous structure. Side channels 117 are preferably formed in a side surface 111B corresponding to a side surface 111A. In another embodiment, the main channels extend in an electrically conductive (5512) substrate along the direction <100> of the crystal plane.

As shown in FIG. 1 and 4, the energy storage device 100 includes a first porous structure, a second porous structure, and a separator 130 between the first and second porous structures. The second porous structure may comprise a plurality of second main channels 121 extending in the second electrically conductive structure 120 at a second acute angle to the second main surface 125, with each of the many second main channels having a second opening 122 on the second main surface 125. In an embodiment of the invention, the plurality the main channels 111 of the first porous structure and the plurality of main channels 121 of the second porous structure are parallel to each other. For example, major surfaces 115, 125 may be formed along the same crystallographic plane. In an embodiment of the invention, a main surface is formed along (1011), (322), (111), or (5512) of the crystallographic plane.

As will be described in detail below, the main channels can be formed in such a way as to reduce the diffusion time constant. In an embodiment of the invention, the main channels are linearly conical. In an embodiment of the invention, the main channels include reservoirs. For example, the main channels may include an hourglass shape with alternating reservoir areas and connecting regions, wherein the reservoir regions are wider than the connecting regions.

As will be described in detail below, the main channels can be formed in such a way as to strengthen the porous structure. For example, a plurality of main channels may include a primary surface shape and a secondary surface shape superimposed on the primary surface shape. In an embodiment of the invention, the primary surface shape is linear or linearly conical. In an embodiment of the invention, the secondary surface shape is sinusoidal. Such a sinusoidal shape change can eliminate abrupt changes in porosity, which reduce the concentration of stresses and strengthen the structure of the porous electrode.

As will be described in detail below, the conditions in the bath for electrochemical etching can also be controlled when the main channels are etched to reduce pore size and increase surface area by reducing the etching temperature during batch processing and increasing the concentration of hydrofluoric acid (HF) of the bath for electrochemical etching to slow down the oxidation and oxide removal sequence.

It will be appreciated that although many of the following changes are described separately, certain embodiments of the invention are not necessarily separate and may be combined under appropriate conditions.

In an embodiment of the invention, a porous electrode is formed by electrochemical etching of a plurality of main channels in an electrically conductive substrate, therefore, each main channel has an opening on a major surface of the electrically conductive substrate, and each of the main channels extends at an acute angle to the main surface in the electrically conductive substrate. Many main channels can be formed at an acute angle along the direction of current flow in the bath for electrochemical etching, or can be formed along the direction of the crystallographic plane in the electrically conductive substrate. In an embodiment of the invention, electrochemical etching involves immersing an electrically conductive substrate in an electrochemical etching bath containing hydrofluoric acid or an organic electrolyte such as dimethyl sulfoxide (DMSO). The electrochemical etching process itself is highly anisotropic, but usually during the electrochemical etching process, the second mechanism of isotropic etching also occurs at a slow speed. This second etching mechanism may include spontaneous oxidation of the electrically conductive substrate (eg, silicon) due to the oxidizing molecules present in the electrochemical etching bath (eg, water) and removal of the resulting oxide with hydrofluoric acid. According to an embodiment of the invention, the number of oxidizing molecules in the bath for electrochemical etching is reduced in order to reduce the speed of the isotropic etching mechanism, resulting in increased anisotropy of the entire etching.

FIG. 8 is a process flow diagram illustrating a method of forming a porous electrode in accordance with an embodiment of the invention. As shown in FIG. , during operation 810, the electrically conductive substrate is immersed in a bath for electrochemical etching. During operation 820, an etching current is applied to the electrically conductive substrate. During operation 830, the etching current is changed nonlinearly to create a porous structure containing a plurality of main channels in the electrically conductive substrate, with each of the main channels having an opening on the main surface of the porous structure.

According to embodiments of the invention, the method illustrated in FIG. 8 can be used to form an energy storage device with a reduced diffusion path length, which reduces the diffusion time constant and makes it possible to operate such energy storage devices at a higher power. The method illustrated in FIG. 8 can also be used during the formation of a porous electrode, such as electrically conductive structures 110 and 120, illustrated in FIG. 1 and 4, or during the formation of other porous structures described below, for example, those related to FIG. 19-21, and FIG. 24-25. In an embodiment of the invention, the change in the etching current in a nonlinear manner during operation 830 includes a change in the etching current in alternating nodes with relatively higher and lower currents. For example, this can lead to alternating regions 910 with the reservoir and connecting regions 920, as shown in the embodiment of the invention illustrated in FIG. 9, where the areas with the tank are wider than the connecting areas. In an embodiment of the invention, the main channels 111 have an average width of approximately 0.05-5 μm, or more precisely, approximately 0.2 μm, and a change in width of approximately 0.01-0.25 μm between the reservoir regions 910 and the connecting regions 920. In an embodiment of the invention the change in the etching current in a nonlinear manner during operation 830 includes a constantly decreasing etching current. For example, this can lead to side walls 111A, 111B with an internal taper from the main surface 115 to the bottom of each of the main channels 111, as shown in the embodiment of the invention illustrated in FIG. 10. In an embodiment of the invention, the width of the lower part of the main channel 111 in the range between 0.01-0.25 μm is smaller than the width of the main channel 111 on the main surface 115. It should be appreciated that while the main channels 111 illustrated in FIG. 9-10 are located at an acute angle to the main surface, such an illustration is indicative and embodiments of the invention are not limited to this. For example, alternating regions with a reservoir and connecting regions, as shown in FIG. 9, or tapering side walls shown in FIG. 10 can be used in the embodiments of the invention illustrated in FIG. 19-21 and FIG. 23B, where the main channels are illustrated as perpendicular to the main surface.

FIG. 11 is a process flow diagram illustrating a method for forming a porous electrode in accordance with an embodiment of the invention. As shown in FIG. 11, during operation 1110, the electrically conductive substrate is immersed in a bath for electrochemical etching. During operation 1120, an etching current is applied to the electrically conductive substrate to create a porous structure containing a plurality of main channels in the electrically conductive substrate, with each of the main channels having an opening on the main surface of the porous structure, and the etching current includes a secondary change in the etching current applied on the primary change in the etching current.

According to embodiments of the invention, the method illustrated in FIG. 11 can be used to form an energy storage device with a reinforced porous structure. The method illustrated in FIG. 11 can also be used to form a porous electrode in structures such as those illustrated in FIG. 1 and 4, the electrically conductive structures 110, 120, or during the formation of other porous structures described below, for example, those related to FIG. 19-21 and FIG. 24-25. In an embodiment of the invention, the primary change in current may be a non-linear change in current. In an embodiment of the invention, the non-linear change in current is close to a second or third order polynomial. In an embodiment of the invention, the secondary current change is a linear addition of a sinusoidal function. Such a sinusoidal change can eliminate sharp changes in porosity, which reduces stress concentration and strengthens the porous structure. FIG. 12 is an illustration of a main channel 111 including side walls 111A, 111B with a primary linear shape and a sinusoidal shape superimposed thereon, where the side walls are substantially parallel. FIG. 13 is an illustration of a main channel 111 including side walls 111A, 111B with a primary linear shape and a sinusoidal shape superimposed on it, where the side walls are conical with an internal taper. In an embodiment of the invention, the main channels have an average width of approximately 0.05-5 μm, or more precisely, approximately 0.2 μm, and the width change along the superimposed secondary form is 2-50 nm, which may be sufficient to eliminate abrupt changes in porosity and remove high stress concentrations. It will be appreciated that while the main channels 111 illustrated in FIG. 12-13 are located at an acute angle to the main surface, such an illustration is indicative and embodiments of the invention are not limited to this. For example, the superposed sinusoidal shapes shown in FIG. 12-13 may be used in the embodiments of the invention illustrated in FIG. 19-21 and FIG. 23B, where the main channels are illustrated as perpendicular to the main surface.

As described above, electrochemical etching can be used to form the porous structure of the porous electrode. In some embodiments, specific etching techniques have been performed to increase the surface or shorten the diffusion path. In some embodiments, the electrochemical etching conditions are further controlled to reduce pore sizes, thereby increasing the surface area of the pores and the capacity of the energy storage device. In an embodiment of the invention, a method for forming a porous electrode includes immersing the electrically conductive substrate in an electrochemical etching bath and applying an etching current to the electrically conductive substrate to create a porous structure containing a plurality of main channels within the electrically conductive substrate, while at the same time supporting approximately room or lower temperature. Standard electrochemical etching processes may not control the bath temperature for electrochemical etching, and often the temperature rises above room temperature during the electrochemical etching process. As the electrochemical etching process is completed, the substrate subjected to this process oxidizes and then the oxide is etched. At higher temperatures, the oxidation and removal process is faster. Accordingly, in an embodiment of the invention, keeping the bath temperature for electrochemical etching within room temperature or lower during electrochemical etching slows down the oxidation process and the oxide etching process results in smaller pores.

In an embodiment of the invention, a method of forming a porous electrode includes immersing the electrically conductive substrate in an electrochemical etching bath that contains a concentration of hydrofluoric acid (HF): alcohol in a ratio of 2: 1, or with a higher concentration of HF, and applying an etching current to the electrically conductive substrate for creating a porous structure containing many main channels inside the electrically conductive substrate. In an embodiment of the invention, the concentration of hydrofluoric acid (HF): alcohol is 3: 1, or a higher concentration of HF. It has been observed that the development of oxidation and etching of the oxide results from a lower concentration of HF. Accordingly, in an embodiment of the invention, the concentration of hydrofluoric acid (HF): alcohol increases for HF to a value of 2: 1, or more specifically 3: 1. In some embodiments of the invention, the temperature of the bath for electrochemical etching is maintained at room temperature or lower, and the concentration of HF: alcohol is at least 2: 1, or more specifically at least 3: 1.

In FIG. 14 shows a method of forming a porous electrode with a matrix of V-grooves or pyramidal recesses in accordance with an embodiment of the invention. During operation 1410, a solid mask pattern is applied to a crystalline substrate to form a matrix of lines. The crystalline substrate is then etched to form a matrix of V-grooves or pyramidal recesses on the main surface of the crystalline substrate during operation 1420. The main surface of the crystalline substrate may be the same main surface of the porous structure as previously described. During operation 1430, a plurality of main channels are electrochemically etched in a crystalline substrate, and many of the main channels have holes in a matrix of V-shaped grooves or pyramidal recesses. Main channels can also be formed with holes on the main surface.

FIG. 15-16 are plan views illustrating a method of forming a matrix of V-grooves and recesses formed in a main surface 115 of a porous structure in accordance with embodiments of the invention. As shown in FIG. 15, a solid pattern of a material such as silicon nitride (Si ₃ N ₄ ) is applied to the crystalline substrate in the form of a matrix of lines 1510. In a separate illustrated embodiment, the crystalline substrate is an electrically conductive substrate 110, as described herein, but others can also be used. substrates, including, but not limited to, an electrically conductive substrate 120. In an embodiment of the invention, the crystalline substrate (100) is a silicon substrate. As shown in FIG. 16, an array of 1660 V-grooves and recesses is etched in a crystalline substrate. In an embodiment of the invention, an array of 1660 V-grooves and recesses is etched in the crystalline silicon substrate (100), thereby forming lateral surfaces 1660A, 1660 B formed along the (111) planes. The etching of the matrix of the V-grooves and recesses may include a suitable etching reagent with higher selectivity for etching in the direction of the <100> plane than in the direction of the <111> plane, for example, such as potassium hydroxide (KOH) solution, ethylene diamine pyrocatechol ( EDP), or tetramethyl ammonium hydroxide (TMAN).

FIG. 17-18 are plan views illustrating a method of forming a matrix of pyramidal recesses formed in a main surface 115 of a porous structure in accordance with an embodiment of the invention. As shown in FIG. 17, a solid template of a material such as silicon nitride (Si ₃ N ₄ ) is applied to the crystalline substrate in the form of a matrix of lines 1510. In a separate illustrated embodiment, the crystalline substrate is an electrically conductive substrate 110, as described here, but other substrates, including, but not limited to, an electrically conductive substrate 120. In an embodiment of the invention, the crystalline substrate (100) is a silicon substrate. As shown in FIG. 18, the matrix 1870 from the pyramidal depressions is etched in the crystalline substrate. In an embodiment of the invention, the matrix 1870 from the pyramidal depressions is etched in the crystalline silicon substrate (100), and side surfaces 1870A, 1870B, 1870C, 1870D are formed along the (111) planes. The etching of the matrix from the pyramidal depressions may include a suitable etching reagent with higher selectivity for etching in the direction of the <100> plane than in the direction of the <111> plane, for example, such as potassium hydroxide (KOH) solution, ethylene diamine pyrocatechol (EDP) or tetramethyl ammonium hydroxide (TMAN).

As shown in FIG. 16 and FIG. 18, when removing the applied lines of the solid pattern 1510 after etching the matrix 1660 of V-grooves or matrix 1870 from the pyramidal depressions, a substantially flat portion of the main surface 115 is opened. However, it should be appreciated that the porous structure including the plurality of main channels, not yet fully formed, and also that the main surface 115 of the porous structure may also correspond to the main surface of the crystalline substrate, or an electrically conductive structure, such as an electrically conductive Ukrainian 110.

FIG. 19-20 are cross-sectional side views illustrating the porous structure of an energy storage device comprising matrixes 1660 of V-grooves or matrixes 1870 of pyramidal recesses, in accordance with an embodiment of the invention after the formation of a plurality of main channels. As illustrated in FIG. 19? 20, a plurality of main channels 111 have openings 112 in a matrix 1660 of V-grooves or a matrix 1870 of pyramidal recesses. In the embodiment of the invention illustrated in FIG. 19, the uppermost flat portions do not exist on the main surface 115 of the crystal substrate 110. In the embodiment of the invention illustrated in FIG. 20, the V-groove matrixes 1660 or the pyramidal recesses matrix 1870 are separated by the uppermost flat sections 116 on the main surface 115 of the crystal substrate 110. The width of the uppermost flat sections 116 or their absence can be controlled by choosing the line width 1510, 1710 of the applied solid pattern .

In the embodiments of the invention illustrated in FIG. 19-20, the main channels 111 are electrochemically etched in the crystalline substrate 110 perpendicular to the flat portions 116 of the main surface 115 where they are presented. For example, where the crystalline substrate is a crystalline silicon substrate (100), the main channels 111 can be electrochemically etched in the direction of the <100> plane perpendicular to the surface (100). It will be appreciated that while the main channels 111 illustrated in FIG. 19-20 are perpendicular to the main surface, such an illustration is indicative, and embodiments of the invention are not limited to this. For example, the main channels 111 could be formed at an acute angle to the main surface due to orientation of the direction of the current transmission line during electrochemical etching.

In FIG. 21 is a cross-sectional side view illustrating an energy storage device according to an embodiment of the invention. As illustrated in FIG. , the energy storage device 100 may include a first and second electrically conductive structure 110, 120 (eg, porous electrodes) and a separator 130 between porous structures within each of the first and second electrically conductive structures 110, 120. Each porous structure contains a V-shaped matrix grooves or pyramidal depressions in the main surface 115, 125 of the porous structure and a plurality of main channels 111, 121 extending in the electrically conductive structures 110, 120 for each of the V-shaped grooves or pyramidal depressions with each of main channels 111, 121 having openings 112, 122 in the corresponding V-shaped groove or pyramidal recess. In the embodiment of the invention illustrated in FIG. 21, a spacer 130 extends into a matrix of V-grooves or pyramidal recesses. In an embodiment of the invention, the second porous structure of the second electrically conductive structure 120 extends into a matrix of V-grooves or pyramidal recesses in the porous structure of the first electrically conductive structure 110. A spacer 130 may be formed on the electrically conductive structure 110 in a variety of different ways. For example, the separator 130 may be created by laying or stacking. In an embodiment of the invention, the spacer 130 is a stretch film placed on the electrically conductive substrate 110.

FIG. 22 is a process flow diagram illustrating a method of forming an energy storage device according to an embodiment of the invention. FIG. 23A-23B are cross-sectional side views illustrating an energy storage device 2300 in accordance with embodiments of the invention. During operation 2210, a separation layer 130 is formed over the first electrically conductive porous electrode containing a plurality of main channels 111, with each main channel having an opening on a major surface 115 of the first electrically conductive porous electrode. A separator 130 may be formed on the first electrically conductive porous electrode using a variety of different methods. For example, the separator 130 may be created by laying or stacking. In an embodiment of the invention, the spacer 130 is a stretch film disposed on a first electrically conductive porous electrode. The electrically conductive porous electrode may be any of the electrically conductive structures described herein. In an embodiment of the invention, the electrically conductive porous electrode is an electrically conductive structure 110, as illustrated in FIG. 1, FIG. 4, FIG. 19-21, or may be any of its variations. In the embodiment of the invention illustrated in FIG. 23A, the main surface 115 is relatively flat. In the embodiment of the invention illustrated in FIG. 23B, a V-groove matrix 1160 or a pyramidal recess matrix 1870 is formed in the main surface 115. The plurality of main channels 111 can extend into the electrically conductive structure 110 perpendicular to the major surface 115 of the porous structure, or can extend into the electrically conductive structure 110 at an acute angle to the major surface 115. During operation 2220, the second electrically conductive porous electrode 2320 is deposited on the separating layer 130 using the deposition technology of the corresponding thin film, such as chemically second vapor deposition (CVD - chemical vapor deposition), coating obtained by centrifugation, coating by vapor deposition (PVD - physical vapor deposition), and coating by electrodeposition. In an embodiment of the invention, the second electrically conductive porous electrode 130 is made of a material such as carbon, a carbon-based material, or a pseudocapacitive material, wherein the first electrically conductive porous electrode is a material selected from the following group: silicon, silicon carbide, germanium, and tin. In an embodiment of the invention, the second electrically conductive porous electrode is made of lithium doped carbon obtained by chemical vapor deposition. In an embodiment of the invention, the second electrically conductive porous electrode is a nanodiamond carbon film. A nanodiamond carbon film can be combined with a heat sink. In the hybrid material embodiments illustrated in FIG. 23A-23B, the first porous electrode may integrate with another circuit 2330 in an electrically conductive substrate. For example, circuit 2330 may be an integrated circuit formed inside an electrically conductive substrate 110, which is also an electrically conductive structure 110 forming a first porous electrode. In an embodiment of the invention, the energy storage device 2300 is located on the same electrically conductive structure 110 as the microprocessor. In another embodiment, the energy storage device 2300 is located on the electrically conductive microprocessor structure 110. In an embodiment of the invention, an energy storage device 2300 is formed inside the housing of a mobile electronic device, such as a mobile phone, laptop, or tablet computer. In an embodiment of the invention, an energy storage device is formed on a silicon bridge connecting two integrated circuit crystals.

As shown in FIG. 24, a method of forming an energy storage device is illustrated in accordance with an embodiment of the invention. During operation 2410, the electrically conductive substrate is etched by an electrochemical method to release the porous structure from the electrically conductive substrate. FIG. 25 is a cross-sectional side view illustrating a porous structure 2512 released from an electrically conductive substrate 2510 in an electrochemical etching bath 2500, in accordance with an embodiment of the invention. For illustrative purposes, the electrochemical etching bath 2500 may include a pair of electrodes 2502, 2504, such as platinum mesh electrodes, mounted on each side of the tub 2506. In another embodiment, the electrochemical etching bath may be a horizontal etching bath. The electrically conductive substrate 2510 can be installed in a removable substrate holder 2520, which can be placed in front of the hole in the separation plate 2530 and fixed in the plate using a bayonet lock. When the latch closes, the left and right compartments are electrically isolated from each other. The electrochemical etching bath 2500 may be filled with a sufficient amount of etching solution 2540 to cover the electrically conductive substrate 2510 and electrodes 2502, 2504. For example, if the substrate contains silicon, representative etching solutions include hydrofluoric acid (HF) solutions and HF along with ethyl alcohol.

Electrochemical etching of the porous structure 2512 in the electrically conductive substrate 2510 may be performed in accordance with conventional techniques. For example, direct current may be maintained between the negative and positive electrodes 2502, 2504. It may be necessary to vary the voltage to some extent during electrochemical etching due to the loss of electrical conductivity of the etching solution 2540 in the bath 2500 for electrochemical etching. In addition, any of the etching process changes described herein may be combined with the method described in relation to FIG. 24, in order, for example, to increase the surface of the porous electrode, reduce the diffusion path length, reduce the pore size, and increase the pore strength. The porous structure 2512 can be etched in the substrate 2510 on the side of the negatively charged electrode 2502. In an embodiment of the invention, the etching mode is used to release the porous structure 2512 from the electrically conductive substrate 2510. For example, the current for electrochemical etching can be rapidly increased to release the porous structure 2512 .

As shown in FIG. 24, the porous structure 2512 may then be attached to the separation layer and the second porous structure to form an energy storage device. This attachment can be accomplished in a variety of ways. For example, the attachment may include deposition of the separation layer on the porous structure. The attachment may include stacking a porous structure on a separation layer, or stacking a separation layer on a porous structure. The attachment may also include stacking a second porous structure on a separation layer. The second porous structure may be formed in the same way, or in a different way, as the porous structure 2512.

FIG. 26 is a block diagram illustrating a mobile electronic device 2600, in accordance with an embodiment of the invention. As illustrated in FIG. 26, the mobile electronic device 2600 comprises a substrate 2610 on which the microprocessor 2620 and an energy storage device 2630 are coupled, interacting with the microprocessor 2620. The energy storage device 2630 can either be located on the substrate 2610 at a distance from the microprocessor 2620, as illustrated by solid lines, or can be located on the microprocessor 2620 itself, as illustrated by dashed lines. In one embodiment of the invention, the energy storage device 2630 comprises first and second electrically conductive structures separated by a separator, where at least one of the structures, i.e. the first and / or second electrically conductive structure, contains a porous structure containing many channels. For example, this embodiment of the invention may be similar to one or more embodiments of the invention shown in any of the previous figures and described in the accompanying text.

In at least some embodiments, the energy storage device 2630 is one of a variety of energy storage devices that can be stacked sequentially (all of these devices are shown in FIG. 26 as a block 2630), which devices are contained within the mobile electronic device 2600. In one or more of these embodiments of the invention, the mobile electronic device 2600 further comprises a switching circuit 2640 that interacts with storage devices energy Ia. When the capacitor is discharged, it does not support a constant voltage, but instead it attenuates exponentially (unlike a battery, where the voltage remains relatively constant during discharge). The switching circuit 2640 contains a circuit or some other mechanism that turns on and off various capacitors, for example, those that maintain a relatively constant voltage. For example, energy storage devices can initially be connected in parallel with each other, and then, after a certain decrease in the voltage value, the subgroup of energy storage devices can be changed due to a switching circuit in order to be connected in series so that their individual contributions to the total voltage may increase the incident overall voltage. In one embodiment of the invention, the switching circuit 2640 can be applied using existing technology for a silicon device that is used in the art (transistors, silicon controlled diodes (SCR), etc.), while in other embodiments, it could be applied using relays or switches of microelectromechanical systems (MEMS), which, as can be noted, tend to have very low resistance.

In some embodiments of the invention, the mobile electronic device 2600 further comprises a sensor network 2650, interacting with devices 2630 for storing energy. In at least some embodiments, each of the plurality of energy storage devices will have its own sensor that displays specific behavioral parameters of the energy storage device. For example, the sensors can display existing voltage levels, as well as the current discharge characteristic, both of which can be used by the switching network, especially when the dielectric material (or other electrical insulator) used is non-linear, and moreover, has a dielectric constant, which changes with voltage. In these cases, it may be preferable, along with the sensor network, to include a state machine, such as voltage regulation module 2660, which takes into account the behavior of the dielectric and reacts accordingly. A voltage control module that predicts dielectric behavior can compensate for any non-linearity. A temperature sensor 2670, which interacts with energy storage devices 2630, can also be included in the system to monitor temperature (or other safety related parameters). In certain embodiments of the invention, the mobile electronic device 2600 further comprises one or more devices: a display 2681, an antenna / radio frequency elements 2682, a network interface 2683, a data input device 2684 (e.g., a keyboard or touch screen), a microphone 2685, a camera 2686, a video projector 2687, a 2688 global navigation and positioning system (GPS) receiver, and the like.

FIG. 27 is a block diagram representing a microelectronic device 2700, in accordance with an embodiment of the invention. As illustrated in FIG. 27, the microelectronic device 2700 comprises: a substrate 2710, a microprocessor 2720 above the substrate 2710, and an energy storage device 2730 cooperating with the microprocessor 2720. The energy storage device 2730 may or may be located on the substrate 2710 spaced from the microprocessor 2720 (eg, die-side capacitor), as illustrated by solid lines, or can be located on the microprocessor 2720 itself (for example, in an embedded layer above the microprocessor), as illustrated by dashed lines. In one embodiment of the invention, the energy storage device 2730 comprises first and second electrically conductive structures separated by a separator, where at least one of the structures, i.e. the first and / or second electrically conductive structure contains a porous structure. For example, this embodiment of the invention may be similar to one or more embodiments of the invention shown in any of the previous figures and described in the accompanying text. In another embodiment, the energy storage device 2730 comprises a plurality of electrically conductive structures containing porous structures that are stacked in series. In an embodiment of the invention, the energy storage device 2730 includes a porous structure that comprises a plurality of main channels extending into the porous structure at an acute angle to the main surface of the porous structure. In an embodiment of the invention, the energy storage device 2730 includes a porous structure that comprises a matrix of V-shaped grooves or pyramidal recesses in the main structure, and a plurality of main channels extend into each V-shaped groove or pyramidal recess. In an embodiment of the invention, the energy storage device 2730 includes a porous structure that includes a plurality of main channels with side walls including a primary surface shape and a secondary surface shape that overlays the primary surface shape. In an embodiment of the invention, the energy storage device 2730 includes a first porous electrode comprising silicon, silicon carbide, germanium, tin, and a pseudocapacitive material, and the energy storage device 2730 includes a second porous electrode containing carbon, a carbon-based material , silicon carbide, and silicon.

The energy storage devices disclosed herein may be used in some embodiments of the invention as an isolation capacitor within a microelectronic device 2700. Such a capacitor is smaller and, for the reasons described elsewhere in the description, offers much higher capacitance and much lower impedance compared with existing decoupling capacitors. As already mentioned, the energy storage device 2730 may be part of an integrated circuit (IC) carrier or microcircuit, or may be located on the microprocessor chip itself. For example, it can, in accordance with embodiments of the invention, form porous silicon regions (or similarly as previously described) on a microprocessor chip, and then create a highly developed surface, with an integrated decoupling capacitor directly on the microprocessor chip substrate. Due to the porosity of silicon, the built-in capacitor will have a very large surface area. Other possible use cases for the disclosed energy storage devices include using a storage device as an element (in which approaches to a problem with size in the z direction by applying the random access built-in random access memory (RAM) can be solved by significantly increasing the farad per unit area), or as a component of voltage converters in the auxiliary voltage circuit, it is possible to use with circuit blocks, individually dual microprocessor cores, or similar devices. In an embodiment of the invention, the energy storage device is integrated inside the electronic device, wherein the energy storage device interacts with the microprocessor. For example, an energy storage device may be formed inside the housing of a mobile electronic device, such as a mobile phone, laptop, or tablet computer. In an embodiment of the invention, an energy storage device is formed on a silicon bridge connecting two integrated circuit crystals.

For example, higher capacitance values in this context could be preferable, since parts of the circuit could in this case operate nominally at a certain (relatively low) voltage, but in this case in places where a higher voltage is necessary in order to increase the speed (for example, a superoperative memory, input / output (I / O) devices, the voltage can be increased to a higher value. An operating circuit of this kind would probably be preferable to a circuit in which a higher voltage; i.e., in cases where only a small part of the circuit requires a higher voltage, it would probably be preferable to increase the voltage relative to a lower base voltage for this small section of the circuit than to lower the voltage relative to a higher base voltage for most of the circuit Future microprocessor generations may also use voltage converters of the type described here. By making available an increase in capacitance for deployment around the kit or around the microprocessor chip, you can help solve the existing problem of unacceptably high inductance between transistors that transmit voltage according to the circuit.

The following examples are provided as separate embodiments of the invention, and they are illustrative rather than limiting.

In a first exemplary embodiment of the invention, an energy storage device includes a porous structure comprising a plurality of main channels within an electrically conductive structure; wherein each of the main channels has an opening on the main surface of the porous structure, and each of the main channels passes into the electrically conductive structure at an acute angle to the main surface. Each main channel can pass into the electrically conductive structure along the direction of the crystalline plane, oriented at an acute angle to the main surface. Side channels can extend from the side surface of each of the main channels into an electrically conductive structure. Where the main surface is the surface (1011), each of the main channels extends into the electrically conductive structure along the direction <100> of the crystalline plane at an acute angle to the main surface. The side channels may also extend from the side surface of each of the main channels passing into the electrically conductive structure along the direction <100> of the crystal plane. Where the main surface is the surface (322), each of the main channels passes into the electrically conductive structure along the direction <100> of the crystalline plane at an acute angle to the main surface. The side channels may also extend from the side surface of each of the main channels passing into the electrically conductive structure along the direction <100> of the crystal plane. Where the main surface is the (111) surface, each of the main channels passes into the electrically conductive structure along the direction <113> of the crystalline plane at an acute angle to the main surface. The side channels may also extend from the side surface of each of the main channels passing into the electrically conductive structure along the direction <113> of the crystal plane. The energy storage device may also include a second porous structure in a second electrically conductive structure, and a separator between the porous structure and the second porous structure. The second porous structure may contain many second main channels, with each of the second main channels having a second hole in the second main surface of the second porous structure, and each of the second main channels passes into the second electrically conductive structure at a second acute angle to the second main surface. The plurality of main channels and the plurality of second main channels may be parallel to each other. The main surface and the second main surface can be formed along the same crystallographic plane, such as the (1011), (322), (111), or (5512) planes. An energy storage device may be integrated inside an electronic device, and may interact with a microprocessor. For example, an energy storage device may be formed inside the housing of a mobile electronic device, such as a mobile phone, laptop, or tablet computer. An energy storage device may be formed on a silicon bridge connecting two integrated circuit crystals. Each of the main channels in the energy storage device may extend into an electrically conductive structure with side walls including a primary surface shape and a secondary surface shape superimposed on the primary surface shape. For example, the primary surface shape may be linear. For example, the primary surface shape may be linearly conical. In an embodiment of the invention, the secondary surface shape is sinusoidal. In an embodiment, the secondary surface shape includes alternating reservoir areas and connecting regions.

In a second exemplary embodiment of the invention, a method for forming a porous electrode includes electrochemical etching of a plurality of main channels in an electrically conductive substrate such that each main channel has an opening in the main surface of the substrate, and each of the main channels extends into the substrate at an acute angle to the main surface. Many main channels can be formed along the direction of current flow in the bath for electrochemical etching. Many main channels can be formed along the direction of the crystallographic plane in the substrate. Electrochemical etching may include immersing the substrate in an electrochemical etching bath containing hydrofluoric acid (HF) or dimethyl sulfoxide (DMSO). The process of electrochemical etching of a plurality of main channels in an electrically conductive substrate may further include immersing the electrically conductive substrate in an electrochemical etching bath, applying an etching current through an electrically conductive substrate, and changing the etching current in a non-linear manner to create a porous structure containing a plurality of main channels inside the electrically conductive substrate. Changing the etching current in a nonlinear manner may include changing the etching current in alternating nodes with a relatively higher and lower current. This can lead to the fact that in each main channel alternating reservoir areas and connecting regions will be contained, moreover, the reservoir regions are wider than the connecting regions. Changing the etching current in a nonlinear manner may include a constant decrease in the etching current. This can lead to the fact that each main channel will contain continuously tapering side walls inward from the main surface to the lower surface of each main channel. Electrochemical etching of the plurality of main channels in the electrically conductive substrate may include immersing the electrically conductive substrate in the bath for electrochemical etching and applying an etching current through the electrically conductive substrate to create a porous structure containing a plurality of main channels inside the electrically conductive substrate, wherein the etching current includes a secondary change etching current superimposed on the primary change in etching current. The primary change in etching current may be a nonlinear change in current. A secondary change in the etching current can be a linear complement to the sinusoidal function. A nonlinear change in current can be approximated by a second or third order polynomial. In an embodiment of the invention, the plurality of main channels comprise side walls with a primary linear shape and a sinusoidal shape superimposed on it. Electrochemical etching of a plurality of main channels in an electrically conductive substrate may include electrochemical etching of an electrically conductive substrate to release a porous structure containing a plurality of main channels from the electrically conductive substrate. Electrochemical etching of a plurality of main channels in an electrically conductive substrate may include maintaining an electrochemical etching bath at approximately room or lower temperature. Electrochemical etching of a plurality of main channels in an electrically conductive substrate may include immersing the electrically conductive substrate in an electrochemical etching bath that contains a concentration of hydrofluoric acid (HF): alcohol in a ratio of 2: 1, or with a higher concentration of HF. In an embodiment of the invention, the electrochemical pickling bath includes a HF: alcohol concentration of 3: 1, or with a higher HF concentration.

In a third exemplary embodiment of the invention, the energy storage device includes a porous structure with an electrically conductive structure, the porous structure comprising a matrix of V-shaped grooves or pyramidal recesses on the main surface of the porous structure, and a plurality of main channels passing into the electrically conductive structure for each V -shaped groove or pyramidal recess, with each main channel having an opening in a corresponding V-shaped groove or pyramidal recess . The main surface may be a plane (100). Each V-shaped groove or pyramidal recess may include a side surface extending along the direction <111> of the plane in the electrically conductive structure. The energy storage device may also include a second porous structure inside the second electrically conductive structure, and a separator between the porous structure and the second porous structure. The separator may extend into a matrix of V-grooves or pyramidal recesses. The second porous structure may extend into a matrix of V-shaped grooves or pyramidal depressions. The second electrically conductive structure may be a material such as carbon, a carbon-based material, and a pseudo-capacitive material. The second porous structure may contain a second matrix of V-shaped grooves or pyramidal recesses in the second main surface of the second porous structure, and the second matrix of main channels extends into the second electrically conductive structure, with each main channel having an opening in a corresponding V-shaped groove or pyramidal recess. The second porous structure may extend into a V-shaped groove or pyramidal recess of the porous structure. The separator can completely fill the matrix of V-shaped grooves or pyramidal recesses. An energy storage device may be formed on a silicon bridge connecting two integrated circuit crystals. Each of the main channels in the energy storage device may extend into an electrically conductive structure with side walls including a primary surface shape and a secondary surface shape superimposed on the primary surface shape. For example, the primary surface shape may be linear. For example, the primary surface shape may be linearly conical. In an embodiment of the invention, the secondary surface shape is sinusoidal. In an embodiment of the invention, the secondary surface shape includes alternating regions with a reservoir and connecting regions. Each of the main channels in the energy storage device may extend into an electrically conductive structure with side walls including a primary surface shape and a secondary surface shape superimposed on the primary surface shape. For example, the primary surface shape may be linear. For example, the primary surface shape may be linearly conical. In an embodiment of the invention, the secondary surface shape is sinusoidal. In an embodiment of the invention, the secondary surface shape includes alternating regions with a reservoir and connecting regions. In an embodiment of the invention, the second porous electrode includes lithium doped carbon. In an embodiment of the invention, the second porous electrode includes a nanodiamond film.

In a fourth exemplary embodiment of the invention, a method of forming a porous electrode includes applying a solid mask pattern to a crystalline substrate to form a matrix of lines, etching a matrix of V-shaped grooves or pyramidal depressions on the main surface of the crystalline substrate, and electrochemically etching a plurality of main channels in the crystalline substrate , each of the many main channels has a hole in the matrix of V-shaped grooves or pyramidal recesses. In an embodiment of the invention, the crystalline substrate is a silicon substrate (100), and the etching of the V-shaped grooves or pyramidal depressions includes an etching reagent - a solution of potassium hydroxide (KOH). The method may also include forming a separator layer above the matrix of V-shaped grooves or pyramidal depressions and depositing a porous electrode on the separator layer. In an embodiment of the invention, the porous electrode is deposited by chemical vapor deposition (CVD). Electrochemical etching of a plurality of main channels in a crystalline substrate may include immersing the crystalline substrate in an electrochemical etching bath and applying an etching current through the crystalline substrate, as well as changing the etching current in a non-linear manner to create a porous structure containing a plurality of main channels in the crystalline substrate, where each of the main channels has a hole on the surface in the matrix of V-shaped grooves or pyramidal recesses. Changing the etching current in a nonlinear manner may include changing the etching current in alternating nodes with a relatively higher and lower current. This can lead to the fact that in each main channel alternating reservoir areas and connecting regions will be contained, moreover, the reservoir regions are wider than the connecting regions. Changing the etching current in a nonlinear manner may include a constant decrease in the etching current. This can lead to the fact that each main channel will contain continuously tapering side walls inward from the main surface to the lower surface of each main channel. Electrochemical etching of a plurality of main channels in a crystalline substrate may include immersing the crystalline substrate in an electrochemical etching bath and applying an etching current through the crystalline substrate to create a porous structure containing a plurality of main channels inside the crystalline substrate, wherein the etching current includes a secondary change etching current superimposed on the primary change in etching current. The primary change in etching current may be a nonlinear change in current. A secondary change in the etching current can be a linear complement to the sinusoidal function. A nonlinear change in current can be approximated by a second or third order polynomial. In an embodiment of the invention, the plurality of main channels comprise side walls with a primary linear shape and a sinusoidal shape superimposed on it. Electrochemical etching of a plurality of main channels in a crystalline substrate may include electrochemical etching of a crystalline substrate to release a porous structure containing a plurality of main channels from the crystalline substrate. Electrochemical etching of a plurality of main channels in a crystalline substrate may include maintaining a bath for electrochemical etching at approximately room or lower temperature. Electrochemical etching of a plurality of main channels in a crystalline substrate may include immersing the crystalline substrate in an electrochemical etching bath that contains a concentration of hydrofluoric acid (HF): alcohol in a ratio of 2: 1, or with a higher concentration of HF. In an embodiment of the invention, the electrochemical pickling bath includes a HF: alcohol concentration of 3: 1, or with a higher HF concentration.

In a fifth exemplary embodiment of the invention, a method of forming a porous electrode includes immersing the electrically conductive substrate in an electrochemical etching bath, applying the etching current through the electrically conductive substrate, and changing the etching current in a non-linear manner to create a porous structure containing many main channels in the electrically conductive substrate, where each of the main channels has a hole on the surface of the porous structure. Changing the etching current in a nonlinear manner may include changing the etching current in alternating nodes with a relatively higher and lower current. This can lead to the fact that in each main channel alternating reservoir areas and connecting regions will be contained, moreover, the reservoir regions are wider than the connecting regions. Changing the etching current in a nonlinear manner may include a constant decrease in the etching current. This can lead to the fact that each main channel will contain continuously tapering side walls inward from the main surface to the lower surface of each main channel.

In a sixth exemplary embodiment of the invention, a method of forming a porous electrode includes immersing an electrically conductive substrate in an electrochemical etching bath, applying an etching current through an electrically conductive substrate to create a porous structure containing a plurality of main channels in the electrically conductive substrate, where each of the main channels has an opening on the main surface of the porous structure, and the etching current includes a change in the secondary etching current superimposed on change in the primary etching current. The change in the primary etching current may be a non-linear change in current. Changing the secondary etching current can be a linear complement to the sinusoidal function. A nonlinear change in current can be approximated by a second or third order polynomial. In an embodiment of the invention, the plurality of main channels comprise side walls with a primary linear shape and a sinusoidal shape superimposed on it.

In a seventh exemplary embodiment of the invention, the energy storage device includes a porous structure comprising a plurality of main channels inside the electrically conductive structure, where each of the main channels has an opening on the main surface of the porous structure, and each of the main channels extends into the electrically conductive structure with side walls, including a primary surface shape and a secondary surface shape, which is superimposed on the primary surface shape. For example, the primary surface shape may be linear. For example, the primary surface shape may be linearly conical. In an embodiment of the invention, the secondary surface shape is sinusoidal. In an embodiment, the secondary surface shape includes alternating reservoir areas and connecting regions.

In an eighth exemplary embodiment of the invention, a method of forming an energy storage device includes forming a separator layer above a first electrically conductive porous electrode, wherein the first electrically conductive porous electrode comprises a plurality of main channels, where each of the main channels has an opening in a main surface of the first electrically conductive porous electrode, and a deposited second electrically conductive porous electrode on the separator layer. The method may also include electrochemical etching of the electrically conductive substrate to form a first electrically conductive porous electrode. The deposition of the second electrically conductive porous electrode may include an operation such as chemical vapor deposition (CVD), a centrifugal coating, vapor deposition (PVD) coating, and electrodeposition coating.

In a ninth exemplary embodiment of the invention, the energy storage device includes a first porous electrode comprising a plurality of main channels, in which each of the main channels has an opening on a main surface of the first porous electrode, and in which the first porous electrode includes silicon, silicon carbide , germanium, or tin; the separator is located on the first porous electrode, and the second electrode is on the separation layer, while the second porous electrode includes silicon, silicon-based material, or pseudocapacitive material. In an embodiment of the invention, the second porous electrode includes lithium doped carbon. In an embodiment of the invention, the second porous electrode includes a nanodiamond film.

In a tenth exemplary embodiment of the invention, a method of forming an energy storage device includes electrochemically etching an electrically conductive substrate to release a porous structure from an electrically conductive substrate, and combining the porous structure with a separation layer and a second porous structure. The connection may include the deposition of the separation layer on the porous structure. The connection may include stacking a porous structure on a separation layer. The connection may include stacking a separation layer on a porous structure. The connection may include stacking a second porous structure on a stacked separation layer. The method may also include electrochemical etching of the second electrically conductive substrate to release a second porous structure from the second electrically conductive substrate.

In an eleventh embodiment of the invention, a method for forming a porous electrode includes immersing the electrically conductive substrate in an electrochemical etching bath, applying an etching current through the electrically conductive substrate to create a porous structure containing a plurality of main channels within the electrically conductive substrate, while maintaining the electrochemical etching in the bath approximately room or lower temperature, with each of the main channels having an opening on the main surface of the porous structure. In an embodiment of the invention, the electrochemical pickling bath includes a solution with a concentration of hydrofluoric acid (HF): alcohol in a ratio of 2: 1, or with a higher concentration of HF.

In a twelfth embodiment of the invention, a method of forming a porous electrode includes immersing the electrically conductive substrate in an electrochemical etching bath, which includes a solution with a concentration of hydrofluoric acid (HF): alcohol in a ratio of 2: 1, or with a higher concentration of HF, and applying current etching through an electrically conductive substrate to create a porous structure containing many main channels inside the electrically conductive substrate, with each of the main channels having an opening on the main surface of the porous structure. In an embodiment of the invention, the electrochemical pickling bath includes a solution with a concentration of hydrofluoric acid (HF): alcohol in a ratio of 3: 1, or with a higher concentration of HF.

Although the invention has been described with reference to specific embodiments of the invention, those skilled in the art will understand that various changes can be made without departing from the scope and spirit of the invention. Accordingly, the disclosure of embodiments of the invention is intended to illustrate the invention, and is not intended to be limiting. It is intended that the scope of the invention be limited only to the extent that is provided by the appended claims. For example, it will be apparent to those skilled in the art that the energy storage devices and related structures and methods discussed herein can be applied to a variety of embodiments of the invention, while the above discussion of some of these options does not necessarily represent a complete description of all possible embodiments of the invention.

In addition, benefits, other advantages, and solutions to problems have been described in relation to specific embodiments of the invention. However, the benefits, advantages, solutions to problems and any element or elements that may lead to any benefits, advantages and solutions to problems in such a way that they take place or become more clearly expressed should not be construed as critical, required, or necessary signs or elements of any or all of the claims.

In addition, the embodiments and limitations described herein are not intended to make the invention publicly available under the doctrine of transferring the invention to public use, if these options and limitations are: (1) vaguely stated in the claims; and (2) are or are potentially equivalent to the elements shown and / or limitations in the claims under the doctrine of equivalents.

Claims (27)

1. An energy storage device comprising:
- a porous structure formed by a plurality of main channels inside the electrically conductive structure in the direction of the crystal plane;
wherein each of the main channels has an opening in the main surface of the crystal and each of the main channels passes into the electrically conductive structure at an acute angle to the main surface of the crystal;
a second porous structure in a second electrically conductive structure and a separator between the porous structure and the second porous structure. 2. A device for storing energy according to claim 1, in which each of the main channels passes into the electrically conductive structure along the direction of the plane of the crystal, oriented at an acute angle to the main surface. 3. An energy storage device according to claim 1, further comprising side channels extending from the side surface of each of the main channels into an electrically conductive structure. 4. A device for storing energy according to claim 1, in which:
- the main surface is the surface (1011), and each of the main channels passes into the electrically conductive structure along the direction (100) of the crystal plane at an acute angle to the main surface;
- the main surface is the surface (322), and each of the main channels passes into the electrically conductive structure along the direction (100) of the crystal plane at an acute angle to the main surface;
- the main surface is the surface (111), and each of the main channels passes into the electrically conductive structure along the direction (113) of the crystal plane at an acute angle to the main surface; or
- the main surface is the surface (5512), and each of the main channels passes into the electrically conductive structure along the direction (100) of the crystal plane at an acute angle to the main surface. 5. The energy storage device according to claim 1, wherein the second porous structure is formed by a plurality of second main channels and each of the second main channels has a second hole in the second main surface of the crystal, and each of the second main channels passes into the second electrically conductive structure under the second acute angle to the second main surface of the crystal; and
in which the main surface and the second main surface are parallel to each other and are formed along the same crystallographic plane. 6. A device for storing energy, containing:
- a porous structure inside the electrically conductive structure, while the porous structure contains a matrix of V-shaped grooves or pyramidal recesses in the main surface of the porous structure; and
a plurality of main channels extending into the electrically conductive structure for each of the V-shaped grooves or pyramidal recesses, each main channel having an opening in a corresponding V-shaped groove or pyramidal recess;
- a second porous structure inside the second electrically conductive structure and a separator between the porous structure and the second porous structure, the separator passing into the matrix of V-shaped grooves or pyramidal recesses. 7. The energy storage device according to claim 6, wherein the second porous structure comprises lithium doped carbon. 8. The energy storage device according to claim 6, wherein the second porous structure comprises a nanodiamond carbon film. 9. The energy storage device according to claim 6, wherein the second porous structure extends into a matrix of V-shaped grooves or pyramidal recesses. 10. The energy storage device according to claim 6, in which the second electrically conductive structure is a material selected from the following group: carbon, carbon-based material and pseudocapacitive material. 11. The energy storage device according to claim 6, wherein the second porous structure comprises a second matrix of V-shaped grooves or pyramidal recesses in the second main surface of the second porous structure; and
- a second matrix of V-shaped grooves or pyramidal recesses extending into the second electrically conductive structure, with each main channel having an opening in a corresponding V-shaped groove or pyramidal recess, and the second porous structure extends into the V-shaped groove or pyramidal recesses of the porous structure. 12. The energy storage device according to claim 6, in which the separator completely fills the matrix of V-shaped grooves or pyramidal recesses. 13. The energy storage device according to claim 1 or 6, wherein the energy storage device is configured to be integrated into an electronic device, wherein the energy storage device is configured to interact with a microprocessor. 14. An energy storage device according to claim 1 or 6, wherein each of the main channels extends into an electrically conductive structure with side walls including a primary surface shape and a secondary surface shape superimposed on the primary surface shape. 15. The energy storage device according to claim 14, wherein the primary surface shape is linearly conical. 16. The energy storage device according to claim 15, wherein the secondary surface shape is sinusoidal. 17. The energy storage device according to claim 14, wherein each of the main channels includes alternating regions with a reservoir and connecting regions. 18. A method of forming a porous electrode, comprising:
- immersion of the electrically conductive substrate in the bath for electrochemical etching; and
- application of the etching current to the electrically conductive substrate;
while the application of the etching current is characterized by:
- changing the etching current in a nonlinear manner to create a porous structure formed by a plurality of main channels in the electrically conductive substrate in the direction of the crystal plane, where each of the main channels has an opening on the main surface of the crystal; or
- the imposition of a secondary change in the etching current on the primary change in the etching current. 19. The method according to p. 18, in which the non-linearly changing etching current comprises changing the etching current in alternating nodes of a relatively higher and lower current. 20. The method according to p. 19, in which the non-linearly changing etching current contains a constantly decreasing etching current. 21. The method according to p. 18, in which the primary change in the etching current is a nonlinear change in the etching current, and the secondary change in the etching current is a linear addition to the sinusoidal function. 22. The method according to p. 21, in which the nonlinear change in the etching current is approximated by a second or third order polynomial. 23. The method according to p. 18, in which the bath for electrochemical etching contains a concentration of hydrofluoric acid (HF): alcohol in a ratio of 2: 1 or with a higher concentration of HF. 24. The method according to p. 18, further comprising maintaining the bath for electrochemical etching at approximately room or lower temperature during the application of the etching current. 25. A method of forming a device for storing energy, comprising:
- electrochemical etching of the electrically conductive substrate to release the porous structure from this electrically conductive substrate; and
- connection of the porous structure with a separation layer and a second porous structure;
- in which the connection contains the deposition of the separation layer on the porous structure. 26. The method according to p. 25, in which the connection comprises stacking a porous structure on a separation layer or laying a stack of a separation layer on a porous structure. 27. The method of claim 25, further comprising electrochemically etching the second electrically conductive substrate to release the second porous structure from the second electrically conductive substrate.

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