JP5941930B2 - Water-based electrolyte energy storage device - Google Patents

Description

  The present invention is directed to aqueous batteries and hybrid energy storage devices, particularly electrochemical storage devices that do not include metal parts in contact with an aqueous electrolyte.

This application is related to US patent application Ser. No. 61 / 450,774 filed Mar. 9, 2011 and March 9, 2011, which is incorporated by reference herein in its entirety. It claims the benefit of the priority of US Patent Application No. 13 / 043,787 (Patent Document 2) filed on the day.

  Small-scale renewable energy harvesting and power generation technologies (solar panels, wind turbines, micro Stirling engines, solid oxide fuel cells, etc.) are prevalent, and in proportion to the medium-scale secondary (rechargeable) energy storage capacity There is a growing need. Batteries for these stationary applications typically store 1-50 kWh of energy (depending on the application) and are historically based on lead-acid (Pb acid) chemistry. Multi-row deep cycle lead acid batteries are known to be assembled at distributed power generation points and last for 1 to 10 years depending on typical duty cycles. These batteries work well to support this application, but lead and acid abuse that pollutes the environment (Pb acid technology is responsible for releasing more than 100,000 tons of Pb into the environment each year in the United States alone. Critical performance degradation when held in an intermediate charge state or cycled to deep discharge levels in accordance with conventional methods, routine maintenance is necessary and necessary to maintain performance There are several problems associated with its use, including the implementation of various reuse programs. There is a strong desire to switch the Pb acid chemical reaction used by the automotive industry. Unfortunately, this is currently a very unattractive option because of the economics of alternative battery chemistry.

  Despite all recent advances in battery technology, there is still no cheap and clean alternative to Pb acid chemistry. This is primarily due to the fact that Pb acid batteries are significantly cheaper than other chemical reactions ($ 200 / kWh) and are now high energy systems for transportation applications (which are inherently much more expensive than Pb acid batteries). The focus is on the development of

US Patent Application No. 61 / 450,774 US Patent Application No. 13 / 043,787 US patent application Ser. No. 12 / 385,277

  One embodiment relates to an electrochemical device comprising a housing and a stack of electrochemical cells in the housing. Each electrochemical cell includes an anode electrode, a cathode electrode, a separator positioned between the anode electrode and the cathode electrode, and an electrolyte. The device is operatively connected to a current collector located between adjacent electrochemical cells, an anode bus operatively connected to the anode of the electrochemical cell in the stack, and a cathode of the electrochemical cell in the stack. The cathode bus is also included. The housing, anode electrode, cathode electrode, separator, anode bus and cathode bus are non-metallic. “Nonmetallic” in the context of this application means a conductive material that is not made of pure metal or metal alloy. Examples of non-metallic materials include, but are not limited to, conductive metal oxides or carbon.

  Another embodiment relates to a method of manufacturing an electrochemical device. The method includes stacking a first non-metallic anode electrode, stacking a first non-metallic separator on the first non-metallic anode electrode, and stacking a first non-metallic cathode electrode on the separator. . The method also includes operably connecting the first non-metallic anode electrode to the non-metallic anode bus and operably connecting the first non-metallic cathode electrode to the non-metallic cathode bus.

  One embodiment relates to an electrochemical device comprising a housing and a stack of electrochemical cells in the housing. Each electrochemical cell includes an anode electrode, a cathode electrode, a separator positioned between the anode electrode and the cathode electrode, and an electrolyte. The apparatus also includes a plurality of carbon cathode and anode current collectors alternating between adjacent electrochemical cells and a plurality of tabs operatively connected to the plurality of carbon cathodes and anode current collectors, wherein the plurality of tabs are electrically Configured to connect to the bus. The cathode electrode of the first electrochemical cell is in electrical contact with the first cathode current collector. The cathode electrode of the second electrochemical cell is in electrical contact with the first cathode current collector. The second electrochemical cell is adjacent to the first side of the first electrochemical cell in the stack. The anode electrode of the first electrochemical cell is in electrical contact with the second anode current collector. The anode electrode of the third electrochemical cell is in electrical contact with the second anode current collector. The third electrochemical cell is adjacent to the second side of the first electrochemical cell in the stack.

  Another embodiment relates to an electrochemical device comprising a housing and a stack of electrochemical cells in the housing. Each electrochemical cell includes a compressed granular anode electrode, a compressed granular cathode electrode, a separator positioned between the anode electrode and the cathode electrode, and an electrolyte. The apparatus also includes a plurality of cathode current collectors and anode current collectors that are alternately positioned between adjacent electrochemical cells. The cathode electrode of the first electrochemical cell is in electrical contact with the first cathode current collector. The cathode electrode of the second electrochemical cell is in electrical contact with the first cathode current collector. The second electrochemical cell is adjacent to the first side of the first electrochemical cell in the stack. The anode electrode of the first electrochemical cell is in electrical contact with the second anode current collector. The anode electrode of the third electrochemical cell is in electrical contact with the second anode current collector. The third electrochemical cell is adjacent to the second side of the first electrochemical cell in the stack.

  Another embodiment relates to an electrochemical device comprising a housing and a plurality of stacks of side-by-side electrochemical cells in the housing. Each electrochemical cell includes an anode electrode, a cathode electrode, a separator positioned between the anode electrode and the cathode electrode, and an electrolyte. The apparatus also includes a current collector located between adjacent electrochemical cells in each of the plurality of stacks. The separator of at least one cell includes a separator sheet that extends continuously between at least two of the plurality of laminates.

  One embodiment relates to an electrochemical device comprising a housing and a stack of electrochemical cells in the housing. Each electrochemical cell includes an anode electrode, a cathode electrode, a separator positioned between the anode electrode and the cathode electrode, and an electrolyte. The apparatus also includes a graphite sheet located between adjacent electrochemical cells in the laminate. The graphite sheet is a current collector for adjacent electrochemical cells.

  Another embodiment is an electrochemical comprising an anode electrode having a plurality of separate anode electrode members separated by an anode boundary region and a cathode electrode having a plurality of separate cathode electrode members separated by a cathode boundary region Regarding cells. The electrochemical cell also includes a separator positioned between the anode and cathode electrodes and an electrolyte. The electrolyte is present in the separator as well as in the boundary area of the anode and cathode electrodes. Furthermore, at least 50% of the anode boundary area across the separator does not line up with the respective cathode boundary area.

  Another embodiment relates to a method of manufacturing an electrochemical device having a stack of electrochemical cells. This method consists of forming a stacked electrochemical cell and pouring an electrically insulating polymer around the stack of electrochemical cells and solidifying the polymer to form a solid insulating shell, or a previously formed solid insulating shell To the periphery of the stack of electrochemical cells.

  Another embodiment relates to a method of manufacturing an electrochemical device. The method includes stacking an anode electrode including a plurality of separate anode electrode members separated by an anode boundary region, stacking a separator over the anode electrode, and a plurality of separate cathodes separated by a cathode boundary region. And stacking a cathode electrode including an electrode member on the separator. At least 50% of the anode boundary area throughout the separator does not form a column with each cathode boundary area, and the plurality of anode electrode members and the plurality of cathode electrode members are arranged in a row and column arrangement.

  Another embodiment relates to a secondary hybrid aqueous energy storage device. The apparatus includes a housing and a stack of electrochemical cells in the housing. Each electrochemical cell includes an anode electrode, a cathode electrode, a separator positioned between the anode electrode and the cathode electrode, and an electrolyte. The apparatus also includes a graphite sheet located between adjacent electrochemical cells. The anode and cathode electrodes are 0.05-1 cm thick.

1 is a schematic view of a columnar laminate of an electrochemical cell according to one embodiment. FIG. 6 is a schematic diagram of the details of a sandwiched current collector according to one embodiment. It is a perspective view of the electrochemical apparatus which has the some columnar laminated body of the electrochemical cell by one Embodiment. FIG. 4 is another perspective view of the embodiment shown in FIG. 3. It is a perspective view of the electrochemical apparatus which has the single columnar laminated body of the electrochemical cell by one Embodiment. FIG. 6 is a perspective view of the embodiment of FIG. 5 with the electrochemical cell removed for ease of understanding. It is a typical sectional side view which shows the detail of one part of embodiment shown in FIG. 2 is a plot of cell potential versus cell capacity for one embodiment. 1 is a schematic representation of one electrochemical cell according to one embodiment of the present invention. (The electrochemical cells can be stacked in a bipolar or columnar stacked arrangement.) 1 is a cross-sectional view of an electrochemical cell in which an anode electrode according to an embodiment is configured with a separate anode electrode member and a cathode electrode is configured with a separate cathode electrode member. (The electrochemical cells can be stacked in a bipolar or columnar stacked arrangement.) 1 is a schematic diagram of an electrochemical device including a bipolar stack of electrochemical cells according to one embodiment of the present invention. It is a plot of cell potential versus storage capacity under charge / discharge conditions over 30 cycles. Figure 2 is a plot of cell charge / discharge capacity and efficiency as a function of cycle.

  Embodiments of the present invention relate to electrochemical energy storage systems such as primary and secondary batteries and hybrid energy storage systems described below. Although the secondary hybrid aqueous energy storage system described below is a preferred embodiment of the present invention, the present invention provides an aqueous system (eg, having an anode and a cathode that intercalates ions from an electrolyte, including Li-ion batteries, etc.). And a battery comprising a non-aqueous electrolyte (eg, a capacitor or pseudo-capacitor anode that stores charge by reversible non-Farade reaction of cations on the electrode (double layer) surface and / or pseudo-capacitance rather than alkali ion intercalation And any suitable electrochemical energy storage system, such as electrolytic capacitors (also known as supercapacitors and ultracapacitors) having a cathode electrode.

  The hybrid electrochemical energy storage system of embodiments of the present invention includes a double layer capacitor, or a pseudo-capacitor electrode (eg, anode) coupled to an active electrode (eg, cathode). In these systems, the capacitor or pseudocapacitor electrode stores charge by the reversible non-Farade reaction and / or pseudocapacitance of alkali cations on the surface of the electrode (double layer), while the active electrode is in the transition metal oxide It causes a reversible Faraday reaction to intercalate and deintercalate alkaline cations similar to batteries.

An example of a system using Na is described in US patent application Ser. No. 12 / 385,277 filed Apr. 3, 2009, which is incorporated herein by reference in its entirety. Has been. This system utilizes a spinel structure LiMn ₂ O ₄ battery electrode, an activated carbon capacitor electrode, and an aqueous Na ₂ SO ₄ electrolyte. In this system, the negative anode electrode stores charge by a reversible non-Farade reaction of Na ions on the activated carbon electrode surface. The positive cathode electrode utilizes a reversible Faraday reaction of Na ion intercalation / deintercalation in spinel lambda MnO ₂ .

In another system, the cathode electrode can include a non-intercalation (eg, non-alkali ion intercalation) MnO ₂ phase. Examples of non-intercalation phases of manganese dioxide include electrolytic manganese dioxide (EMD), alpha phase and gamma phase.

FIG. 1 shows a columnar laminate 100P of an electrochemical cell 102 according to one embodiment. In this embodiment, each of the electrochemical cells 102 in the columnar laminate 100P includes an anode electrode 104, a cathode electrode 106, and a separator 108 positioned between the anode electrode 104 and the cathode electrode 106. The electrochemical cell 102 also includes an electrolyte between the anode electrode 104 and the cathode electrode 106 (ie, an electrolyte that has penetrated the separator and / or electrode). Each of the electrochemical cells 102 of the columnar laminate 100P can be mounted in the frame 112 (see FIGS. 9 to 10). Furthermore, the columnar laminated body 100P can be enclosed in the housing 116 instead or in addition (see FIGS. 3 to 6). Additional features of the housing 116 are described in more detail below in connection with the embodiment shown in FIGS. Further embodiments of the electrochemical cell 102 are shown in FIGS. 9 and 10 and are discussed in more detail below. The columnar stacked body 100 </ b> P also includes a plurality of carbon cathodes and anode current collectors 110 a and 110 c that are alternately disposed between adjacent electrochemical cells 102. The current collector can include any suitable form of conductive carbon such as expanded graphite, carbon fiber paper, or an inert substrate coated with a carbon material. Preferably, the current collector comprises graphite having a density greater than 0.6 g / cm ³ .

  In one embodiment, the columnar laminate 100P includes a plurality of conductive contacts (eg, tabs) 120 operatively connected to a plurality of carbon cathode and anode current collectors 110a, 110c. The conductive contact 120 can be attached to one side of the carbon cathode and anode current collectors 110a, 110c. Alternatively, as shown in FIG. 2, the conductive contact portion 120 can be disposed between two carbon current collectors 110a or 110c to form a sandwich structure 110s. Preferably, the columnar stacked body 100P also includes two electric buses 122a and 122c. One electric bus 122a is electrically connected to the anode current collector 110a in the columnar stacked body 100P, and one electric bus 122c is connected to the cathode current collector 110c in the columnar stacked body 100P. In one embodiment, the electrical connection from the anode and cathode current collectors 110a, 110c to the electrical buses 122a, 122c is via the conductive contacts 120. In this way, the electrochemical cells 102 in the stacked body 100P can be electrically connected in parallel.

  In one embodiment, positive cathode bus 122c electrically connects cathode electrode 106 of electrochemical cell 102 in stack 100P to the positive electrical output of the stack, and negative anode bus 122a is stacked. The anode electrode 104 of the electrochemical cell 102 in 100P is electrically connected in parallel to the negative electrical output of the laminate 100P.

  In the columnar stacked body 100 </ b> P, the cathode current collector 110 c can be positioned between adjacent electrochemical cells 102. That is, the plurality of pairs of electrochemical cells 102 are “front-to-front” and “back-to-back” configurations. As an example, consider a columnar laminate 100P in which the first electrochemical cell 102 is in the center of the laminate 100P. In the first pair of cells 102, the first cathode current collector 110c has a second electrochemical cell in which the cathode electrode 106 of the first electrochemical cell 102 is in electrical contact with the first cathode current collector 110c. The cathode electrode 106 of 102 is also positioned so as to be in electrical contact with the first cathode current collector 110c. The second electrochemical cell 102 is adjacent to the first (cathode) side of the first electrochemical cell in the columnar stacked body 100P.

  The third electrochemical cell 102 is adjacent to the second (anode) side of the first electrochemical cell 102 in the columnar stacked body 100P. The anode electrode 104 of the first electrochemical cell 102 is in electrical contact with the first anode current collector 110a, and the anode electrode 104 of the third electrochemical cell 102 is also electrically connected to the first anode current collector 110a. Contact. The stack can be continued in this way. Therefore, the produced columnar laminate 100P can include a plurality of electrochemical cells 102 in which adjacent anode electrodes 104 and adjacent cathode electrodes 106 are alternately stacked in a front-and-front and back-and-back pair.

  The columnar stacked body 100P can be described in the axial direction. In the case of the stacked body 100P shown in FIG. 1, the axial direction is parallel to the buses 122a and 122c. The electrochemical cells 102 in the stacked body 100P are stacked in the axial direction along the axis of the stacked body 100P. Each of the odd or even numbered electrochemical cells 102 in the stack includes a cathode electrode 106 facing the first end of the axis of the stack 100P and a second end opposite the axis of the stack 100P. An anode electrode 104 facing the surface. The other of the even-numbered or odd-numbered electrochemical cells 102 in the stacked body 100P includes a cathode electrode 106 facing the second end of the axis of the stacked body 100P, and a first electrode on the opposite side of the axis of the stacked body 100P. And an anode electrode 104 facing the end portion.

  In one embodiment, the columnar laminate 100P includes an electrochemical cell 102 in which the anode electrode 104 and / or the cathode electrode 106 are made of compressed granular pellets. The anode electrode 104 and the cathode electrode 106 can be 0.05-1 cm thick. Alternatively, the anode electrode 104 and the cathode electrode 106 are 0.05 to 0.15 cm thick. The boundary area between the compressed granular pellets can be an electrolyte reservoir, as described in more detail below.

In one embodiment, electrochemical cell 102 is a secondary hybrid aqueous energy storage device. In one embodiment, the active cathode electrode 106 reversibly intercalates alkali metal cations. The anode electrode 104 is a capacitive electrode that stores charge by a reversible non-Farade reaction of alkali metal cations on the surface of the anode electrode 104 or a pseudo-charge that causes partial charge transfer surface interaction with the alkali metal cation on the surface of the anode electrode 104 Capacitive electrodes can be included. In one embodiment, the anode is an electrochemically stable pseudocapacitive or electrochemical double layer capacitive material of less than -1.3 V relative to a standard hydrogen electrode (NHE). In one embodiment, the cathode electrode 106 can comprise a doped or undoped cubic spinel λ MnO _{2 type} material or a NaMn ₉ O ₁₈ tunnel orthorhombic material and the anode electrode 104 can comprise activated carbon. Alternatively, the cathode electrode can include a non-intercalated MnO ₂ phase such as electrolytic manganese dioxide (EMD), alpha or gamma phase.

  Another embodiment of the present invention is shown in FIGS. In this embodiment, the electrochemical device 300 includes eight stacks 100P of electrochemical cells 102 in a 2 × 4 array. However, any number of stacked bodies 100P can be included. For example, the electrochemical device 300 includes two stacks 100P in a 1 × 2 array, three stacks 100P in a 1 × 3 array, twelve stacks 100P in a 3 × 4 array, or a 5 × 5 array. Twenty-five stacked bodies 100P can be included. The exact number of stacks 100P can be selected according to the end user's desire or power demand.

  Electrochemical device 300 preferably includes a housing 116. In this embodiment, the housing 116 includes a base 116b and a plurality of sidewall members 116a. In one embodiment, the anode electrode 104 and cathode electrode 106 of the electrochemical cell 102 in each of the plurality of stacks 100P are exposed along their edges but are constrained by the housing 116. Preferably, the housing 116 pressurizes the entire laminate 100P, thereby stabilizing the laminate 100P of the electrochemical device 300. In another embodiment, the anode electrode 104 and the cathode electrode 106 of the electrochemical cell 102 in each of the plurality of stacks 100P are partially or completely covered and constrained along their edges. This can be achieved, for example, by attaching the anode electrode 104 and the cathode electrode 106 of each cell 102 to a frame 112 as shown in FIG. Other housing structures can be used. For example, the housing 116 can include a base 116b and a single integral sidewall member 116a similar to a glass bell.

  In this embodiment, the separator 108 and / or the anode current collector 110a and / or the cathode current collector 110c of the at least one electrochemical cell 102 continuously extend between at least two of the plurality of stacked bodies 100P. . Preferably, the separator 108, the anode current collector 110a, and the cathode current collector 110c extend continuously between all the stacked bodies 100P in the electrochemical device 300. In this way, the electrochemical device 300 can be manufactured easily and inexpensively. However, the cathode electrode 106 and the anode electrode 104 of each cell 102 in the cell stack 100P preferably do not extend continuously to another cell 102 in another one of the stack 100P. In one embodiment, the space between the electrodes 104, 106 of the adjacent stack 100P includes an electrolyte storage part.

  In one embodiment, electrochemical device 300 further includes a composite positive bus and first end plate 122c that electrically connects to all positive outputs of the plurality of stacks, and a plurality of stacks 100P. A composite negative bus and a second end plate 122a that are electrically connected to all of the negative outputs. Further, the base 116b can include an external electrical contact 124 that can quickly and easily attach the electrochemical device 300 to the load device.

In one embodiment, the electrochemical device 300 is the hybrid electrochemical device described above. Preferably, in this embodiment, all the electrochemical cells 102 of the stack 100P of the electrochemical cells 102 are hybrid electrochemical cells. Similar to the previously discussed embodiment, the hybrid electrochemical cell 102 comprises a cathode electrode 106 comprising doped or undoped cubic spinel λ MnO _{2 type} material or NaMn ₉ O ₁₈ tunnel structure orthorhombic material, and an anode comprising activated carbon. The electrode 104 can be included, and the electrolyte includes an aqueous electrolyte including sodium ions. As discussed below, alternative cathode and anode materials can be used. In another embodiment, the device can include a secondary battery such as a Li-ion or Na-ion battery.

  Another embodiment of the present invention is shown in FIGS. In this embodiment, the illustrated electrochemical device 500 includes a single columnar stack 100P of electrochemical cells 102. More than one laminate can be used. A single columnar stack 100 </ b> P of the electrochemical cell 102 is in the housing 116. The electrochemical device 500 includes an anode bus 122a and a cathode bus 122c. Each of the anodes 104 in the electrochemical cell 102 in the columnar stacked body 100P is electrically connected to the anode bus 122a via the anode current collector 110a. In this embodiment, the anodes 104 are connected in parallel. Similarly, each of the cathodes 106 in the electrochemical cell 102 in the columnar stacked body 100P is electrically connected to the cathode bus 122c via the cathode current collector 110c. In this embodiment, the cathodes 106 are connected in parallel. Preferably, anode current collector 110a and cathode current collector 110c are connected to respective anode bus 122a and cathode bus 122c by conductive tab 120. Current collectors 110a, 110c may be connected to respective tabs 120 and / or anodes and cathodes by pressure / friction fittings, conductive electrochemically inert cured coatings, or conductive electrochemically inert cured epoxies. It can be operatively connected to the buses 122a, 122c. The electrochemical device 500 also includes an external electrical contact 124 for supplying electricity from the electrochemical device 500 to an external device or circuit. In one embodiment, the external electrical contact 124 is located on the anode bus 122a and the cathode bus 122c. Alternatively, the contact can be located at the bottom or side of the bus. The contacts can be located on the same side of the device or on different sides.

  In one embodiment, all of the components of electrochemical device 500 that typically contact the electrolyte (ie, anode 104, cathode 106, separator 108, current collector 110, bus 122, tab 120, and housing 116) are non-metallic materials. Made of. In one embodiment, current collector 110, bus 122, and tab 120 can be made of any suitable conductive form of carbon. Buses and tabs can be made of graphite, carbon fiber, or carbon-based conductive composites (eg, a polymer matrix containing carbon fiber or filler material). The housing 116 can be made of, but not limited to, an electrochemically inert electrically insulating polymer. In this way, the electrochemical device 500 is corrosion resistant. If the bus 122 does not contact the electrolyte (ie, if the tab extends through the sealing material to the external bus), the bus can be made of metal. The external electrical contact portion 124 can be made of a metal material. In the embodiment shown in FIG. 7, the bus 122 is surrounded by an airtight sealant 114 located between the upper portion of the bus 122, the upper portion of the columnar laminate 100 </ b> P of the electrochemical cell 102, and the contact portion 124. The encapsulant can include an electrolyte and an oxygen impermeable polymer or epoxy material, such as a poly-based epoxy, an adhesive, a calk or a melt sealed polymer. The bus 122 can be connected to the contact 124 by pressure provided by soldering, bolts, clamps, and / or sealing materials. In this way, the external electrical contact 124 can be insulated from the electrolyte, thereby making the external electrical contact 124 of a metal material such as copper. Thus, only the metal contact or interconnect 124 protrudes from the sealant 114 region of the housing 116.

  FIG. 8 is a plot of cell potential versus cell capacity for one embodiment of an electrochemical device 500. As can be seen in the plot, a high cell capacity such as over 1,200 mAh can be obtained at a voltage of 0.5 V or less.

FIG. 9 illustrates one embodiment of the electrochemical cell 102. The electrochemical cell 102 includes an anode electrode 104, a cathode electrode 106, and a separator 108 between the anode electrode 104 and the cathode electrode 106. The electrochemical cell 102 also includes an electrolyte between the anode electrode 104 and the cathode electrode 106. In one embodiment, separator 108 can be porous with electrolyte present in the pores. The electrolyte may be aqueous or non-aqueous. The electrochemical cell 102 can also include a graphite sheet 110 that serves as a current collector for the electrochemical cell 102. Preferably, the graphite sheet 110 is densified. In one embodiment, the density of the graphite sheet 110 is greater than 0.6 g / cm ³ . The graphite sheet 110 can be made of expanded graphite, for example. In one embodiment, the graphite sheet 110 can include one or more foil layers. Suitable materials for the anode electrode 104, cathode electrode 106, separator 108, and electrolyte are discussed in more detail below.

  The anode electrode 104, the cathode electrode 106, the separator 108, and the graphite sheet current collector 110 can be mounted in a frame 112 that seals individual cells. The frame 112 is preferably made of an electrically insulating material, such as an electrically insulating plastic or epoxy. The frame 112 can be made of a preformed ring, an injection epoxy, or a combination of the two. In one embodiment, the frame 112 can include separate anode and cathode frames. In one embodiment, the graphite sheet current collector 110 can be configured to act as a sealant 114 along with the frame 112. That is, the graphite sheet current collector 110 can extend as a recess in the frame 112 and serve as the sealing material 114. In this embodiment, the sealant 114 prevents electrolyte from flowing from one electrochemical cell 102 to the adjacent electrochemical cell 102. In another embodiment, another encapsulant 114 such as a washer, gasket, etc. can be provided to prevent the graphite sheet current collector from functioning as an encapsulant.

  In one embodiment, the electrochemical cell is a hybrid electrochemical cell. That is, the cathode electrode 106 in operation reversibly intercalates alkali metal cations, and the anode electrode 104 (1) reversible non-Farade reaction of alkali metal cations on the anode electrode surface, or (2) It includes a capacitive electrode that stores charge by a pseudocapacitive electrode that undergoes partial charge transfer surface interaction with the alkali metal cation on the anode electrode surface.

  FIG. 11 shows a bipolar stack 100B of an electrochemical cell 102 according to another embodiment. In contrast to conventional electrochemical cell stacks that include separate anode-side and cathode-side current collectors, the bipolar stack 100B has a single graphite sheet current collector 110 cathode of one electrochemical cell 102. It operates in a state where it is located between the electrode 106 and the anode electrode 104 of the adjacent electrochemical cell 102. Therefore, the bipolar laminate 100B uses only half the current collector of the conventional electrochemical cell laminate.

  In one embodiment, the bipolar laminate 100B is encased in an outer housing 116 and includes conductive headers 118 on the top and bottom of the bipolar laminate 100B. The header 118 preferably includes a corrosion-resistant current collecting metal including but not limited to aluminum, nickel, titanium and stainless steel. Preferably, pressure is applied when assembling the bipolar laminate 100B. The pressure helps to provide a good seal that prevents electrolyte leakage.

  In one embodiment, electrochemical cell 102 is a secondary hybrid aqueous energy storage device. In this embodiment, the anode electrode 104 and the cathode electrode 106 can be 0.05-1 cm thick, such as 0.05-0.15 cm thick.

  FIG. 10 shows another embodiment of the present invention. In this embodiment, the anode electrode 104 can include separate anode electrode members 104a separated by an anode boundary region 104b. Further, the cathode electrode 106 can include separate cathode electrode members 106a separated by a cathode boundary region 106b. As shown, the anode electrode 104 includes two separate anode electrode members 104a and the cathode electrode 106 includes three separate cathode electrode members 106a. However, this is merely an example. The anode electrode 104 and the cathode electrode 106 can each include any number of separate anode electrode members 104a and separate cathode electrode members 106a. Further, in one embodiment, the anode boundary region 104b and the cathode boundary region 106b can include voids filled with electrolyte.

Furthermore, FIG. 10 only shows a one-dimensional cross section. The cross-sectional view in the orthogonal direction can also show the anode electrode 104 and the cathode electrode 106 having a separate anode electrode member 104a and a separate cathode electrode member 106a. That is, the anode electrode 104 and the cathode electrode 106 can constitute a two-dimensional checkered pattern. In other words, separate anode electrode members 104a and separate cathode electrode members 106a can be arranged in a row and column arrangement. The individual anode electrode members 104a and the individual cathode electrode members 106a can be, for example, square or rectangular. In one embodiment, the inventor of the present application provides structural integrity of the electrochemical cell 102 when the anode electrode 104 and the cathode electrode 106 are provided with a different number of separate anode electrode members 104a and cathode electrode members 106a. I found it to improve. In this embodiment, the anode rows and columns are offset from the cathode rows and columns. In one embodiment, at least 50%, such as 50-100%, including 75-95% of the anode boundary area 104b throughout the separator 108 does not line up with the respective cathode boundary area 106b. Alternatively, the anode electrode 104 and cathode electrode 106 may include the same number of separate cathode electrode member 106a and another number of anode electrode member 104a. In another embodiment, the anode electrode 104 or the cathode electrode 106 can comprise a single unitary sheet and the other electrode comprises a checkered discrete member.

  In one embodiment, the anode electrode member 104a and the cathode electrode member 106a are made from rolled sheets or pressed pellets of activated carbon and manganese oxide, respectively. Another embodiment relates to a method of manufacturing the electrochemical device of FIG. The method includes (1) stacking anode electrodes 104 including a plurality of separate anode electrode members 104a separated by an anode boundary region 104b, (2) stacking separators 108 on the anode electrode 104, and (3 ) Stacking a cathode electrode 106 including a plurality of separate cathode electrode members 106a separated by a cathode boundary region 106b on a separator 108; In one aspect, at least 50% of the anode boundary region 104b does not line up with the respective cathode boundary region 106b throughout the separator 108. The method can also include stacking the graphite sheet current collector 110 on the cathode electrode 106. The anode electrode member 104a and / or the cathode electrode member 106b can be formed by cutting the members 104a, 106a from a rolled sheet of anode or cathode material or by pressing a pellet of anode or cathode material. .

  Another embodiment of the present invention relates to a method of manufacturing a stack 100B, 100P of an electrochemical cell 102. The method can include forming a stacked electrochemical cell and pouring an electrically insulating polymer around the stack 100B, P of the electrochemical cell 102. The method can also include solidifying the polymer to form a solid insulating shell or frame 112. Alternatively, the method can include applying a pre-formed solid insulating shell 112 around the stack of electrochemical cells 102. The polymer can be, but is not limited to, epoxy or acrylic.

  The method may also include attaching the conductive end plate header 118 shown in FIG. 11 to the top and bottom of the laminate 110. The laminate 110 and solid insulating shell or frame 112 can then be placed in a hollow cylindrical shell or outer housing 116. The method also includes placing a graphite sheet current collector 110 between adjacent electrochemical cells 102 in the stack 100B, P of electrochemical cells 102. In one embodiment, each electrochemical cell 102 in the stack 100B, P of electrochemical cells 102 includes an anode electrode 104 having an active anode region and a cathode electrode 106 having an active cathode region. As shown in FIG. 9, the graphite sheet current collector 110 can have a region larger than the active anode region and the active cathode region, which acts as a sealing material.

(Equipment parts)
Several materials including cathode transition metal oxides, sulfides, phosphates or fluorides can be used as active cathode materials capable of reversible Na ion intercalation / deintercalation. In embodiments of the present invention, materials suitable for use as the active cathode material preferably include alkali atoms such as sodium, lithium, or both prior to use as the active cathode material. The active cathode material need not include Na and / or Li as it is formed (ie, prior to use in an energy storage device). However, electrolyte-derived Na cations must be able to be incorporated into the active cathode material by intercalation during operation of the energy storage device. Thus, the material that can be used as the cathode in the present invention need not necessarily contain Na as formed, but reversible interfacing of Na ions without significant overvoltage loss during the energy storage device discharge / charge cycle. Includes materials that are capable of calation / deintercalation.

  In embodiments where the active cathode material contains alkali atoms (preferably Na or Li) prior to use, some or all of these atoms will deintercalate during the first cell charge cycle. Electrolyte-derived alkali cations (overwhelmingly Na cations) re-intercalate during cell discharge. This is different from almost all hybrid capacitor systems that require an intercalation electrode opposite the activated carbon. In most systems, electrolyte-derived cations adsorb to the anode during the charge cycle. At the same time, counter anions such as hydrogen ions in the electrolyte intercalate into the active cathode material, thus maintaining the charge balance of the electrolyte solution, but drastically reducing the ion concentration. During discharge, cations are liberated from the anode and anions are liberated from the cathode, maintaining the charge balance of the electrolyte solution, but increasing the ion concentration. This is a different mode of operation than the device in the embodiments of the present invention in which hydrogen ions or other anions are preferably not intercalated into the cathode active material.

Suitable active cathode material may have during use, the general formula A _x M _y O _z. Where A is Na or a mixture of Na and one or more of Li, K, Be, Mg and Ca, x is in the range of 0 to 1 (including 0 and 1) before use, and during use. Is in the range of 0-10 (including 0 and 10), M includes any one or more transition metals, y is in the range of 1-3 (including 1 and 3), preferably 1.5-2 .5 (including 1.5 and 2.5), O is oxygen, z is in the range 2-7 (including 2 and 7), preferably in the range 3.5-4.5. (Including 3.5 and 4.5).

In the general formula A _x M _y O part of the active cathode material of _z, Na ions reversibly intercalates / deintercalating during the discharge / charge cycle of the energy storage device. Thus, the amount x in the active cathode material formula varies during device use.

In the general formula A _x M _y O part of the active cathode material of _z, A includes optionally in combination with Li, Na, K, Be, at least 50at% of at least one or more of Mg or Ca, M Includes any one or more transition metals, O is oxygen, x is in the range of 3.5 to 4.5 before use, 1 to 10 in use, y is 8.5 to 8.5 The range is 9.5, and z is in the range of 17.5 to 18.5. In these embodiments, A preferably comprises at least 51 at% Na, such as at least 75 at% Na, and 0-49 at% Li, K, Be, Mg or Ca, such as 0-25 at%, M Includes one or more of Mn, Ti, Fe, Co, Ni, Cu, V or Sc, x is about 4 before use, 0 to 10 during use, and y is about 9. And z is about 18.

In the general formula A _x M _y O part of the active cathode material of _z, A comprises Na or at least 80 atomic percent of Na and Li, K, Be, and mixtures of one or more of Mg and Ca. In these embodiments, x is preferably about 1 before use and ranges from 0 to about 1.5 during use. In some preferred active cathode materials, M includes one or more of Mn, Ti, Fe, Co, Ni, Cu and V, and includes one or more of Al, Mg, Ga, In, Cu, Zn and Ni. It can be doped (less than 20 at%, such as 0.1-10 at%, for example 3-6 at%).

Common classes of suitable active cathode materials include (but are not limited to) layered / orthorhombic NaMO ₂ (bannesite), cubic spinel-based manganate (eg, λMnO ₂ -based material where M is Mn) MO ₂ such as Li _x M ₂ O ₄ (1 ≦ x <1.1) before use, Na _y Mn ₂ O ₄ during use, Na ₂ M ₃ O ₇ system, NaMPO ₄ system , NaM ₂ (PO ₄ ) ₃ series, Na ₂ MPO ₄ F series, and tunnel structure Na _0.44 MO ₂ . In all formulas, M contains at least one transition metal. Typical transition metals can be Mn or Fe (for cost and environmental reasons), but (among others) Co, Ni, Cr, V, Ti, Cu, Zr, Nb, W, Mo or combinations thereof. It can be used to replace Mn, Fe or combinations thereof in whole or in part. In embodiments of the present invention, Mn is a preferred transition metal. In some embodiments, the cathode electrode can include a plurality of active cathode materials in a homogeneous or near-homogeneous mixture or laminated within the cathode electrode.

In some embodiments, the initial active cathode material comprises NaMnO ₂ (Bernite structure), optionally doped with one or more metals such as Li, Al.
In some embodiments, the first active cathode material comprises a λMnO ₂ (ie, a cubic isomorph of manganese oxide) based material, optionally doped with one or more metals such as Li, Al, and the like.

In these embodiments, the cubic spinel λMnO ₂ is formed by first forming a lithium-containing manganese oxide such as lithium manganate (eg, cubic spinel LiMn ₂ O ₄ or a nonstoichiometric variant thereof). Can do. In embodiments utilizing a cubic spinel λMnO ₂ active cathode material, most or all of Li is electrochemically or chemically extracted from the cubic spinel LiMn ₂ O ₄ to form a cubic spinel λMnO _{2 type} material (ie, A material with a Mn: O ratio of 1: 2 and / or a material in which Mn may be replaced with another metal and / or a material that also contains an alkali metal and / or a Mn: O ratio is not necessarily 1: 2. Material) can be formed. This withdrawal can occur as part of an initial device charge cycle. In such cases, Li ions are deintercalated during the first charge cycle from the cubic spinel LiMn ₂ O ₄ as formed. By discharge, Na ions derived from the electrolyte are intercalated into cubic spinel λMnO ₂ . Thus, the formula of the active cathode material in operation is Na _y Li _x Mn ₂ O ₄ (possibly doped with one or more additional metals, preferably Al as described above). Here, 0 <x <1, 0 <y <1, and x + y ≦ 1.1. Preferably, the quantity x + y varies from about 0 (full charge) to about 1 (full discharge) with a charge / discharge cycle. However, values greater than 1 during full discharge can be used. In addition, any other suitable forming method can be used. A non-stoichiometric Li _x Mn ₂ O ₄ material with more than 1 Li for every 2 Mn and 4 O atoms can be used as the initial material, from which the cubic spinel λMnO ₂ is formed. (For example, 1 ≦ x <1.1). Thus, the cubic spinel λ manganate has the formula Al _z Li _x Mn _2−z O ₄ (1 ≦ x <1.1 and 0 ≦ z <0.1) before use, and Al _z during use. Li _x Na _y Mn ₂ O ₄ (0 ≦ x <1.1, 0 ≦ y <1, 0 ≦ x + y <1.1, and 0 ≦ z <0.1, Al may be replaced with another dopant. Can have).

In some embodiments, the initial cathode material comprises Na ₂ Mn ₃ O ₇ , optionally doped with one or more metals such as Li, Al.
In some embodiments, the initial cathode material comprises Na ₂ FePO ₄ F, optionally doped with one or more metals such as Li, Al.

In some embodiments, the cathode material comprises Na _0.44 MnO ₂ , optionally doped with one or more metals such as Li, Al. This active cathode material can be produced by thoroughly mixing Na ₂ CO ₃ and Mn ₂ O ₃ in an appropriate molar ratio and firing at, for example, about 800 ° C. The degree of Na content incorporated into this material during firing determines the oxidation state of Mn and how it locally binds O ₂ . This material was shown to circulate between 0.33 <x <0.66 for Na _x MnO ₂ in non-aqueous electrolytes.

In some cases, the cathode electrode is comprised of one or more active cathode materials (eg, 1-49%, such as 2-10% by weight of minor components such as orthorhombic tunnel structure materials ), high surface area conductive diluents (conductive Grade graphite, carbon black such as acetylene black, non-reactive metals, and / or conductive polymers, etc.), binders, plasticizers, and / or fillers. Exemplary binders are polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC) based composites (including PVC-SiO ₂ composites), cellulosic materials, polyvinylidene fluoride (PVDF), hydrated banesite (When the active cathode material includes another material), may include another non-reactive non-corrosive polymeric material, or a combination thereof. Composite cathodes can be formed by mixing a portion of one or more preferred active cathode materials with a conductive diluent and / or a polymer binder and pressing the mixture into pellets. In some embodiments, the composite cathode electrode can be formed from a mixture of about 50-90 wt% active cathode material. The balance of the mixture includes one or more combinations of diluents, binders, plasticizers and / or fillers. For example, in some embodiments, a composite cathode electrode can be formed from about 80 wt% active cathode material, about 10-15 wt% diluent such as carbon black, and about 5-10 wt% binder such as PTFE.

One or more additional functional materials can optionally be added to the composite cathode to increase capacity and replace the polymer binder. These arbitrarily selected materials include, but are not limited to, Zn, Pb, hydrated NaMnO ₂ (bernesite), and hydrated Na _0.44 MnO ₂ (orthorhombic tunnel structure). When hydrated NaMnO ₂ (bernite) and / or hydrated Na _0.44 MnO ₂ (orthorhombic tunnel structure) is added to the composite cathode, the resulting device has a dual function material composite cathode.
The cathode electrode generally has a thickness of about 40-800 μm.

The anode anode may comprise any material capable of reversibly storing Na ions by surface adsorption / desorption (electrochemical double layer reaction and / or pseudocapacitive reaction (ie, partial charge transfer surface interaction)). And a sufficient capacity in a desired voltage range. Exemplary materials that meet these requirements include porous activated carbon, graphite, mesoporous carbon, carbon nanotubes, disordered carbon, Ti oxide materials (such as titania), V oxide materials, phospho-olivine materials, and other suitable materials Mesoporous ceramic materials, and combinations thereof. In a preferred embodiment, activated carbon can be used as the anode material.

In some cases, the anode electrode may include one or more anode materials, high surface area conductive diluents (such as conductive grade graphite, carbon black such as acetylene black, non-reactive metals, and / or conductive polymers), PTFE, Includes binders, plasticizers, and / or fillers, such as PVC-based composites (including PVC-SiO ₂ composites), cellulosic materials, PVDF, other non-reactive non-corrosive polymer materials, combinations thereof It can be in the form of a composite anode. A composite anode can be formed by mixing a portion of one or more preferred anode materials with a conductive diluent and / or a polymer binder and pressing the mixture into pellets. In some embodiments, the composite anode electrode can be formed from a mixture of about 50-90 wt% anode material. The balance of the mixture includes one or more combinations of diluents, binders, plasticizers and / or fillers. For example, in some embodiments, the composite anode electrode can be formed from about 80 wt% activated carbon, about 10-15 wt% diluent such as carbon black, and about 5-10 wt% binder such as PTFE.

One or more additional functional materials can optionally be added to the composite anode to increase capacity and replace the polymer binder. These arbitrarily selected materials include, but are not limited to, Zn, Pb, hydrated NaMnO ₂ (bernesite), and hydrated Na _0.44 MnO ₂ (orthorhombic tunnel structure).
The anode electrode generally has a thickness of about 80-1600 μm.

Electrolytes Electrolytes that are useful in embodiments of the present invention include salts that are sufficiently dissolved in water. For example, the electrolyte is zero of at least one anion selected from the group consisting of SO ₄ ²⁻ , NO ₃ ⁻ , ClO ₄ ⁻ , PO ₄ ³⁻ , CO ₃ ²⁻ , Cl ⁻ and / or OH ^−. 1M-10M solution can be included. Thus, Na cation-containing salts include (but are not limited to) Na ₂ SO ₄ , NaNO ₃ , NaClO ₄ , Na ₃ PO ₄ , Na ₂ CO ₃ , NaCl and NaOH or combinations thereof.
In some embodiments, the electrolyte solution may be substantially free of Na. In these examples, the cation in the anion salt can be an alkali (such as K) or alkaline earth (such as Ca or Mg) cation other than Na. Accordingly, salts containing alkali cations other than Na include (but are not limited to) K ₂ SO ₄ , KNO ₃ , KClO ₄ , K ₃ PO ₄ , K ₂ CO ₃ , KCl and KOH. Exemplary alkaline earth cation-containing salts include CaSO ₄ , Ca (NO ₃ ) ₂ , Ca (ClO ₄ ) ₂ , CaCO ₃ and Ca (OH) ₂ , MgSO ₄ , Mg (NO ₃ ) ₂ , Mg ( CIO ₄ ) ₂ , MgCO ₃ and Mg (OH) ₂ . Electrolyte solutions substantially free of Na can be prepared from any combination of such salts. In another embodiment, the electrolyte solution can include a solution of a Na cation-containing salt and one or more non-Na cation-containing salts.

The molarity is preferably 100 ° C. for aqueous Na ₂ SO ₄ solutions, depending on the desired performance characteristics of the energy storage device and the degradation / performance limiting mechanisms associated with higher salt concentrations. In the range of about 0.05M to 3M, such as about 0.1 to 1M. Similar ranges are preferred for other salts.

  Blends of different salts (such as sodium-containing salts and one or more blends of alkali, alkaline earth, lanthanide, aluminum and zinc salts) can result in an optimized system. Such a blend provides an electrolyte comprising a sodium cation and one or more cations selected from the group consisting of alkali (such as K), alkaline earth (such as Mg, Ca), lanthanide, aluminum and zinc cations. be able to.

In some cases, the pH of the electrolyte can affect the OH concentration by adding some additional OH ⁻ ionic species to make the electrolyte solution more basic, for example, by adding another OH-containing salt with NaOH. Can be changed by adding certain other compounds that affect the pH, such as H ₂ SO ₄ which makes the electrolyte solution more acidic. The pH of the electrolyte affects the range of the cell voltage stability window (relative to the reference electrode) and may also affect the stability and degradation of the active cathode material, inhibiting proton (H ⁺ ) intercalation. Can do. Proton (H ⁺ ) intercalation can play a role in active cathode material capacity loss and cell degradation. In some cases, the pH can be increased to 11-13 to make different active cathode materials stable (rather than being stable at neutral pH 7). In some embodiments, the pH can be in the range of about 3-13, such as about 3-6, about 8-13, etc.

In some cases, the electrolyte solution includes an additive that mitigates the degradation of the active cathode material, such as a birnessite material. Exemplary additives include, but are not limited to, it may be a Na ₂ HPO ₄ in an amount sufficient to obtain a concentration 0.1 mm to 100 mm.

Separator The separator used in embodiments of the present invention can comprise a cotton sheet, PVC (polyvinyl chloride), PE (polyethylene), glass fiber or any other suitable material.

Operational Characteristics As described above, in embodiments where the active cathode material contains alkali atoms (preferably Na or Li) prior to use, some or all of these atoms will deintercalate during the first cell charge cycle. . Electrolyte-derived alkali cations (overwhelmingly Na cations) re-intercalate during cell discharge. This is different from almost all hybrid capacitor systems that require an intercalation electrode opposite the activated carbon. In most systems, electrolyte-derived cations adsorb to the anode during the charge cycle. At the same time, counter anions in the electrolyte intercalate into the active cathode material, thus maintaining the charge balance of the electrolyte solution, but drastically reducing the ion concentration. During discharge, cations are liberated from the anode and anions are liberated from the cathode, maintaining the charge balance of the electrolyte solution, but increasing the ion concentration. This is a different mode of operation from the device in the embodiment of the present invention.

A hybrid energy storage device having the columnar / parallel electrical connection shown in FIG. 1A and the physical structure shown in FIGS. The apparatus comprises a three level (two each) anode 104 / cathode 106 set having expanded graphite sheet current collectors 110a, 110c structure (500 micron thick) and nonwoven fiber separator material 108 as shown in FIG. Was included. The cathode contained a λMnO ₂ phase active material as described above and was made from compressed granules of active material, carbon black, graphite powder and PTFE. The anode contained activated carbon mixed with carbon black and PTFE. Pressure was applied to bring each graphite anode and cathode current collector 110a, 110c into contact with a respective anode and cathode graphite bus 122a, 122c that served as the positive and negative buses of the device. A polypropylene housing 116 was used to house the device and the graphite bus bars 122a, 122c were threaded through appropriately sized holes in the polypropylene housing and then the polypropylene was sealed with a silicone adhesive material. Next, the copper wire was connected to the external (non-electrolyte contact) bus bar 124 coming out of the housing under pressure, and the entire external bus wire was covered with potting epoxy.

  The apparatus was then subjected to 15 formation cycles and then tested for energy storage capacity and stability through multiple cycles. FIG. 12 shows the results of this test. FIG. 12 (a) shows device potential versus storage capacity under charge / discharge conditions exceeding 30 cycles. Cycling was performed at the C / 6 current rating. The capacity of the device was about 1.1 Ah. The data show that the cycle-by-cycle voltage profiles overlap almost completely, indicating that the system is extremely stable, has no capacity loss, and has no internal corrosion. FIG. 12 (b) is a plot of cell charge / discharge capacity as a function of cycle. There is no capacity loss as a function of cycle through at least 60 cycles. Another cell's data indicates that this should be maintained through thousands of cycles. Furthermore, the coulombic efficiency was found to be 98-100% in these cycles.

  According to this embodiment, a highly stable aqueous electrolyte hybrid energy storage device is made without using metal in the battery casing. This device exhibits excellent stability and is highly expected for long-term use in various energy storage applications.

  Although the foregoing description refers to certain preferred embodiments, it should be understood that the invention is not so limited. Those skilled in the art will recognize that various modifications can be made to the disclosed embodiments and that such modifications are intended to be within the scope of the present invention. All publications, patent applications and patents cited herein are hereby incorporated by reference in their entirety.

Claims (6)

An electrochemical device,
A housing;
A stack of electrochemical cells in the housing, each electrochemical cell comprising:
A compressed granular anode electrode;
A compressed granular cathode electrode;
A separator located between the anode electrode and the cathode electrode;
An electrolyte, and a laminate including:
A plurality of cathode and anode current collectors alternately located between adjacent electrochemical cells,
The cathode electrode of the first electrochemical cell is in electrical contact with the first cathode current collector;
A cathode electrode of a second electrochemical cell is in electrical contact with the first cathode current collector, and the second electrochemical cell is adjacent to a first side of the first electrochemical cell in the stack. And
An anode electrode of the first electrochemical cell is in electrical contact with a second anode current collector;
An anode electrode of a third electrochemical cell is in electrical contact with the second anode current collector, and the third electrochemical cell is adjacent to a second side of the first electrochemical cell in the stack. And
And the anode electrode includes a plurality of separate anode electrode members separated by an anode boundary region;
The cathode electrode includes a plurality of separate cathode electrode members separated by a cathode boundary region;
The electrolyte is present in the separator and in the anode and cathode electrode boundary regions;
An electrochemical device wherein at least 50% of the anode boundary area does not line up with the respective cathode boundary area throughout the separator . An electrochemical device,
A housing;
A stack of electrochemical cells in the housing, each electrochemical cell comprising:
A compressed granular anode electrode;
A compressed granular cathode electrode;
A separator located between the anode electrode and the cathode electrode;
An electrolyte, and a laminate including:
A plurality of cathode and anode current collectors alternately located between adjacent electrochemical cells,
The cathode electrode of the first electrochemical cell is in electrical contact with the first cathode current collector;
A cathode electrode of a second electrochemical cell is in electrical contact with the first cathode current collector, and the second electrochemical cell is adjacent to a first side of the first electrochemical cell in the stack. And
The anode electrode of the first electrochemical cell is in electrical contact with the second anode current collector, the anode electrode of the third electrochemical cell is in electrical contact with the second anode current collector, and A third electrochemical cell is adjacent to the second side of the first electrochemical cell in the stack;
An electrochemical device, wherein the electrochemical device is a hybrid aqueous electrolyte energy storage device. The electrochemical device according to claim 2 .
An electrochemical device wherein the cathode comprises an alkali ion intercalation material and the anode is an electrochemically stable pseudocapacitive or electrochemical double layer capacitive material of less than -1.3 V relative to NHE. The electrochemical device according to claim 3 .
An electrochemical device in which the cathode electrode includes a doped or undoped cubic spinel λ MnO _{2 type} material or a NaMn ₉ O ₁₈ tunnel structure orthorhombic material, the anode electrode includes activated carbon, and the electrolyte includes sodium ions. The electrochemical device according to claim 3 .
An electrochemical device in which the anode electrode includes one or more of porous activated carbon, mesoporous carbon, carbon nanotube, pseudocapacitive metal oxide material, or a composite thereof. The electrochemical device according to claim 2 .
The electrolyte can interact with both the anode and the cathode so that charge can be stored via intercalation at the cathode electrode and further by a pseudo-capacitive non-Farade surface reaction at the anode electrode. An electrochemical device that is an aqueous solution containing dissolved alkali ions.

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