阅读说明：本技术 双层氢氧化物（dlh）型化合物及其在用于具有石墨和树脂复合物以及电解质的能量存储设备的电极中的用途 (Double-layer hydroxide (DLH) type compounds and their use in electrodes for energy storage devices with graphite and resin composites and electrolytes ) 是由 弗朗索瓦·吉尼恩 珍-玛丽·吉尼恩 于 2019-07-11 设计创作，主要内容包括：本公开涉及包含二价和三价镍离子的双层氢氧化物型化合物,以及除了在先前开发的使用Fe～(2+)和Fe～(3+)的“绿锈相关化合物”的电极中的用途以外,此类化合物在用于能量存储设备的电极中的用途。(The present disclosure relates to double-layered hydroxide-type compounds comprising divalent and trivalent nickel ions, and uses of Fe in addition to those previously developed 2+ And Fe 3+ In addition to the use of "patina-related compounds" in electrodes, the use of such compounds in electrodes for energy storage devices.)

1. A compound having the formula:

[Ni^II _8(1-x)Ni^III _8xO₁₆H_2(9-4x)]²⁺ A^2-

wherein x is 0 to 1, and A^2-Is an anion having a charge of-2,

wherein the compound has a double-layered hydroxide-type structure.

2. The compound of claim 1, wherein a^2-Is CO₃ ^2-。

3. The compound of any one of the preceding claims, wherein the compound is in a crystalline form having a crystal size of 50nm to 1500 nm.

4. The compound of claim 3, wherein the crystals have a crystal size of about 100 nm.

5. The compound of any one of the preceding claims for use in an electrode of an energy storage device.

6. A material for an electrode of an energy storage device, the material comprising a compound of any one of claims 1-4.

7. The material of claim 6, wherein the material is a composite further comprising a binder.

8. The material of claim 7, wherein the material further comprises graphite.

9. An electrode for an energy storage device comprising the material of any one of claims 6-8.

10. The electrode of claim 9, wherein the electrode is a cathode when the energy storage device is discharged.

11. The electrode of claim 9, wherein the electrode is an anode when the energy storage device is discharged.

12. An energy storage device comprising the electrode of any one of claims 9-11.

13. The energy storage device of claim 12, further comprising a second electrode comprising formula Fe^II _6(1-y)Fe^III _6yO₁₂H_2(7-3y)CO₃Wherein y is 0 to 1.

14. The energy storage device of claim 13, wherein x is 1 and y is 0.

15. The energy storage device of claim 13, wherein x is 0 and y is 1.

16. Any of claims 12 to 15An energy storage device as described further comprising being CO₃ ^2-/HCO₃ ^-An electrolyte of a buffer.

17. The energy storage device of claim 16, wherein the electrolyte has a pH of about 8 to about 12.

18. The energy storage device of claim 17, wherein the electrolyte has a pH of about 10.

19. A process for preparing a compound according to any one of claims 1 to 4, said process comprising:

(a) coprecipitation of Ni in an oxygen-free atmosphere^IISalt and Ni^IIISalt, wherein the ratio x { [ Ni ]³⁺]/([Ni²⁺]+[Ni³⁺]) Equal to 1/4 to give a compound of the formula Ni^II ₆Ni^1II ₂(OH)₁₆CO₃A compound of (1); and

(b) adding hydrogen peroxide under oxygen-free atmosphere to enable formula Ni^II ₆Ni^1II ₂(OH)₁₆CO₃Deprotonation of said compound to give the compound Ni^III ₈O₁₆H₁₀CO₃。

20. A method of making the energy storage device of any of claims 12-18, comprising:

(a) preparing a compound according to any one of claims 1-4 by a process according to claim 19;

(b) combining the compound obtained in step (a) with graphite and a first binder to form a first composite;

(c) preparing a first electrode from the first composite material;

(d) providing a second electrode comprising a second composite material, wherein the second composite material comprises graphite, a second binder, and Fe^II _6(1-y)Fe^III _6yO₁₂H_2(7-3y)CO₃Wherein y is 0 to 1;

(e) providing an electrolyte that is CO having a pH of about 8 to about 12₃ ^2-/HCO₃ ^-A buffering agent; and

(f) assembling the first electrode, the second electrode, and an electrolyte to provide the energy storage device.

21. The method of claim 20, wherein Ni is added to the mixture^II _8(1-x)Ni^III _8xO₁₆H_2(9-4x)CO₃In the formula, x is 1; and in Fe^II _6(1-y)Fe^III _6yO₁₂H_2(7-3y)CO₃In (A), y is 0.

22. The method of claim 20, wherein Ni is added to the mixture^II _8(1-x)Ni^III _8xO₁₆H_2(9-4x)CO₃In which x is 0 and in Fe^II _6(1-y)Fe^III _6yO₁₂H_2(7-3y)CO₃In (a), y is 1.

23. The method of claim 20, wherein the first electrode and the second electrode are initially in a trivalent state.

24. The method of any one of claims 20-23, wherein the first binder is a resin.

25. The method of any one of claims 20-24, wherein the second binder is a resin.

26. The method of any one of claims 20-25, wherein the buffer has a pH of about 10.

Technical Field

The present disclosure relates to Double Layer Hydroxide (DLH) type compounds comprising divalent and trivalent nickel ions, and the use of such compounds in electrodes for energy storage devices.

Background

Energy storage devices (e.g., secondary/rechargeable batteries, and accumulators) typically include a positive electrode, a negative electrode, and an electrolyte. Conventionally, the positive electrode is the cathode when discharging, and the negative electrode is the anode when discharging. As used herein, the term "cathode" refers to the positive electrode in a discharge cycle, while the term "anode" refers to the negative electrode in a discharge cycle.

Disclosure of Invention

In one aspect, there is provided a composition having the formula [ Ni^II _8(1-x)Ni^III _8xO₁₆H_2(9-4x)]²⁺[A^2-nH₂O]Wherein x is 0 to 1, and A^2-Is an anion of charge-2; wherein the compound has a Double Layered Hydroxide (DLH) type structure.

In some embodiments, A^2-Is CO₃ ^2-。

The water molecules incorporated into the double-layered hydroxide material are redox-treatedThe process does not work. Water molecules may occupy the middle layer (interlayer) by two COs₃ ^2-Sites left by the ions. For Ni^II-Ni^IIIDLH material, [ Ni ]^II _8(1-x)Ni^III _8xO₁₆H_2(9-4x)]²⁺[A^2-nH₂O]If a is the distance between cations in a hexagonal road surface (hexagonal pavement), the lattice parameter of the unit cell is (4 × a). Thus, there are 16 possible sites in a unit cell, and water molecules can fill up to 10 of these sites, since each CO is present₃ ^2-The ions occupy three sites (one in the nabla configuration and the other in the delta configuration); they may be fewer than 10 (n.ltoreq.10) and are therefore randomly distributed. For Fe^II-Fe^IIIDLH material [ Fe ]^II _6(1-y)Fe^III _6yO₁₂H_2(7-3y)]²⁺[CO₃ ^2-mH₂O]^2-The unit cell is (2 √ 3 × a) corresponding to 12 sites, and water molecules can fill up 6 of these sites at most (m ≦ 6). However, all water molecules present in these materials do not play a role in the deprotonation-protonation process (as described below), and therefore the number of water molecules present is not relevant to the function of the material used as an electrode. Therefore, from now on, they will not be mentioned again in all formulae, which can be written on the one hand as Ni^II _8(1-x)Ni^III _8xO₁₆H_2(9-4x)CO₃On the other hand, it can be written as Fe^II _6(1-y)Fe^III _6yO₁₂H_2(7-3y)CO₃。

In some embodiments, the compound is in the form of flat hexagonal crystals (platelets) having a size of 50nm to 1500 nm. In some embodiments, the crystals generally have a crystal size of about 100 nm.

In some embodiments, the compounds are used in electrodes of energy storage devices.

In another aspect, there is provided a material for an electrode of an energy storage device, the material comprising a compound as defined in any one of the embodiments above.

In some embodiments, the material is a composite further comprising a binder.

In some embodiments, the material further comprises graphite.

In another aspect, there is provided an electrode for an energy storage device comprising a material as defined in any one of the embodiments above.

In some embodiments, the electrode is a cathode when the energy storage device is discharged.

In some embodiments, the electrode is an anode when the energy storage device is discharged.

In another aspect, there is provided an energy storage device comprising an electrode as defined in any one of the embodiments above.

In some embodiments, the energy storage device further comprises a second electrode comprising Fe^II _6(1-y)Fe^III _6yO₁₂H_2(7-3y)CO₃Wherein y is 0 to 1. In some embodiments, x is 1 and y is 0. In other embodiments, x is 0 and y is 1.

In some embodiments, the energy storage device further comprises an electrolyte, the electrolyte being CO₃ ^2-/HCO₃ ^-A buffer of (2). In some embodiments, the pH of the electrolyte is from about 8 to about 12. In some embodiments, the pH of the electrolyte is about 10.

In another aspect, there is provided a compound of formula Ni as defined in any one of the embodiments above^II _8(1-x)Ni^III _8xO₁₆H_2(9-4x)CO₃A process for the preparation of a compound of (a), which process comprises:

□ coprecipitation of Ni in an oxygen-free atmosphere^IISalt and Ni^IIISalt, wherein the ratio x { [ Ni ]³⁺]/([Ni²⁺]+[Ni³⁺]) Equal to 1/4 to give the formula Ni^II ₆Ni^III ₂(OH)₁₆CO₃A compound of (1); and

□ by rapid addition of hydrogen peroxide in an oxygen-free atmosphere^II ₆Ni^III ₂(OH)₁₆CO₃Deprotonation of the compound (a) to give the compound Ni^III ₈O₁₆H₁₀CO₃。

In another aspect, there is provided a method of manufacturing an energy storage device as defined in any of the above embodiments, including:

□ preparation of Ni of formula as defined in any one of the examples above by the process defined above^II _8(1-x)Ni^III _8xO₁₆H_2(9-4x)CO₃A compound of (1);

□ combining the compound obtained in step (a) with graphite and a first resin binder to form a first composite;

□ preparing a first electrode, such as a flat sheet, from the first composite material;

□ providing a second electrode comprising a second composite material, wherein the second composite material comprises graphite, a second resin binder, and Fe^II _6(1-y)Fe^III _6yO₁₂H_2(7-3y)CO₃Wherein y is 0 to 1;

□ provides an electrolyte that is CO having a pH of about 8 to about 12₃ ^2-/HCO₃ ^-A buffering agent; and

□ the first electrode, second electrode and electrolyte are assembled to provide to the energy storage device.

In some embodiments, in Ni^II _8(1-x)Ni^III _8xO₁₆H_2(9-4x)CO₃In which x is 1 and in Fe^II _6(1-y)Fe^III _6yO₁₂H_2(7-3y)CO₃In (A), y is 0.

In some embodiments, in Ni^II _8(1-x)Ni^III _8xO₁₆H_2(9-4x)CO₃In the formula, x is 0; whileIn Fe^II _6(1-y)Fe^III _6yO₁₂H_2(7-3y)CO₃In (a), y is 1.

In some embodiments, the first binder is a resin.

In some embodiments, the second binder is a resin.

In some embodiments, the buffer has a pH of about 10.

Drawings

FIG. 1 shows Fe^II _6(1-x)Fe^III _6xO₁₂H_2(7-3x)CO₃And the corresponding voltammetric cycle of the material, wherein x (molar ratio of ferric iron) can vary from 0 to 1. The "patina" observed in steel corrosion is DHL at x 1/3.

FIG. 2 is LiFePO₄And FePO₄Schematic representation of the crystal structure of (a).

Detailed Description

Existing rechargeable lithium ion batteries are widely used in a variety of devices and applications, but have various disadvantages. For example, such batteries are not very "environmentally friendly" and may require special precautions to be taken upon recycling. Such batteries also require a long charging time. Furthermore, the costs associated with lithium are high due to the rarity of the lithium ore deposits from which the batteries are obtained.

The first generation of lithium ion batteries commercialized by Sony (Sony) in 1991 were based on the reversible exchange of lithium ions between a cathode (e.g., a lithium transition metal oxide such as lithium cobalt dioxide or lithium manganese oxide) and a graphite anode. It is desirable to use an aprotic electrolyte (i.e., an electrolyte without acidic hydrogen atoms), such as LiPF dissolved in a mixture of ethylene carbonate and propylene or tetrahydrofuran₆Salt to avoid degradation of the very reactive electrode. The main advantage of such batteries is their relative charge-discharge speed within a limited margin, and they are therefore used primarily in electronic devices, but also in hybrid vehicles. Unfortunately, they cannot withstand large discharges, as this can lead to their rapid degradation.

The second generation lithium ion batteries, called lithium iron phosphate batteries, utilize LiFePO₄A cathode and a graphite anode. Since their energy density is slightly higher than LiCoO₂Batteries have been widely used in robotics because of their energy density, but they have an energy density three times less than conventional lead batteries because of the fact that lead has a density comparable to that of iron (the density of the lead to the rest of the iron). They can withstand more charge cycles and therefore have longer battery life than other lithium ion batteries; nor does it necessarily favor (convor) partial charging (i.e., favoring charging the battery to less than 100%, or avoiding fully discharging the battery). They support high amperage (amps), enabling them to generate large amounts of power and recharge quickly. They have fewer fire hazards than other lithium ion batteries and can be used at temperatures up to 70 ℃. Moreover, the resulting voltage stability is very high over substantially the entire discharge cycle. Finally, lithium iron phosphate batteries are less polluting because they last longer and can be stored for a longer time due to lead poisoning (also known as lead poisoning) caused by exposure to lead and because their energy density drops more slowly. The main disadvantage of lithium iron phosphate batteries is that the discharge rate drops sharply at around 80% of discharge. Furthermore, the costs associated with lithium are high due to the rarity of the lithium ore deposits from which the batteries are obtained. Even small amounts of lithium can be a health hazard.

LiFePO as an active mineral compound₄Has the same crystal structure as olivine, and consists of entangled octahedra and tetrahedra (see fig. 2). The structure shows Li⁺The channels through which ions can migrate despite their large size. The deformation due to the tension to which the material is subjected may result in the passage not remaining perfectly straight; therefore, Li is introduced during discharge⁺Ions become increasingly difficult, which also limits the speed of the charge-discharge cycle.

The active compound of lithium iron phosphate batteries can be written as Fe^II _(1-x)Fe^III _xLi_(1-x)PO₄. When x is 1, the process is finishedIn the fully charged trivalent iron state, it is Fe^IIIPO₄. When x is 0, it is LiFe in the ferrous state at the time of full discharge^IIPO₄。

From LiFe^IIPO₄Extracting lithium to charge the cathode can be written as:

charging: li Fe^IIPO₄-x Li⁺-x e^-→x Fe^IIIPO₄+(1-x)Li Fe^IIPO₄。

Lithium intercalated Fe^IIIPO₄To discharge the cathode, thus becoming:

discharging: fe^IIIPO₄+x Li⁺+x e^-→x Li Fe^IIPO₄+(1-x)Fe^IIIPO₄。

Examples of oxyhydroxy salts of ferrous-ferric iron (oxyhydroxysalts) related to the family of layered hydroxides are described in U.S. patent No. 9,051,190, the disclosure of which is incorporated herein by reference and attached hereto as appendix a). These double-layer hydroxide compounds ("DLH") are made of layers containing divalent and trivalent cations in the center of an octahedron, the vertices of which are bound by hydroxyl groups (OH)^-) Ion occupancy. In these layers (which are in contact with Fe)^II(OH)₂The same layer as observed in (c) an intermediate layer comprising anions and water molecules is interposed; this will induce a mixture of divalent and trivalent cations to balance the charges. From a technical point of view, the special case of divalent and trivalent cations belonging to the same element in all possible DLHs leads to new most interesting properties. In the case of iron, a family of ferrous-ferric compounds is available, called "patina", because they occur during the corrosion of steel. When exposed to hydrogen peroxide H₂O₂These "patina" can rapidly oxidize; the oxidation is via OH^-Ion deprotonation is carried out in situ, thereby obtaining a fully ferric compound in which the original crystal structure is fully preserved. Among all possible anions to be intercalated, the carbonate ion CO was chosen in view of their stability₃ ^2-. Is of the formula Fe^III ₆O₁₂H₈CO₃. According to the method used for any "carbonized patina" synthesis, wherein the molar ratio x { [ Fe ] of trivalent iron³⁺]/([Fe²⁺]+[Fe³⁺]) Is 1/3, corresponding to the formula Fe^II ₄Fe^III ₂(OH)₁₂CO₃) By coprecipitation of two salts, one ferrous and one ferric, to form the active compound. Coprecipitation in a glove box under nitrogen atmosphere and immediately pouring a large amount of hydrogen peroxide to obtain Fe in the form of trivalent iron^III ₆O₁₂H₈CO₃. Cyclic voltammetry results in the general formula Fe^II _6(1-x)Fe^III _6xO₁₂H_2(7-3x)CO₃(wherein x is 0 to 1) protonation-deprotonation of a compound. In the fully charged ferric state, when x is 1, the formula is Fe^III ₆O₁₂H₈CO₃And in the fully discharged ferrous state, when x is 0, it is Fe^II ₆O₁₂H₁₄CO₃. LiFePO can be used₄Analogy is made to the case of cathodes in which protons H⁺In place of Li ion⁺。

In Fe^II ₆O₁₂H₁₄CO₃Middle OH^-Deprotonation of the ions to charge the electrodes can be written as:

charging: fe^II ₆O₁₂H₁₄CO₃-6xH⁺-6x e^-→x Fe^III ₆O₁₂H₈CO₃+(1-x)Fe^II ₆O₁₂H₁₄CO₃。

In Fe^III ₆O₁₂H₈CO₃Middle O^2-Or OH^-The ions are protonated to discharge the electrodes, becoming:

discharging: fe^III ₆O₁₂H₈CO₃+6x H⁺+6x e^-→x Fe^II ₆O₁₂H₁₄CO₃+(1-x)Fe^III ₆O₁₂H₈CO₃。

Thereby obtaining an active compound for a battery electrode. However, contrary to the case of lithium iron phosphate batteries, it is not possible to use graphite (as intercalation compound) for the second electrode.

Accordingly, it is desirable to provide a second electrode that can be used with the above-described electrode comprising Fe^II _6(1-x)Fe^III _6xO₁₂H_2(7-3x)CO₃Electrodes of the compound are used together.

The present disclosure describes a new material with a double-layer hydroxide-type structure that can be used as a second electrode in an energy storage device that employs the formula Fe in its first electrode^II _6(1-x)Fe^III _6xO₁₂H_2(7-3x)CO₃The double layer hydroxide type compound of (1).

The material has the general formula: [ Ni ]^II _8(1-x) Ni^III _8x O₁₆ H_2(9-4x)]²⁺A^2-Wherein x is 0 to 1, and A^2-Is an anion of charge-2. In particular, A^2-May be CO₃ ^2-。

In particular, the material may have the formula [ Ni^II _8(1-x) Ni^III _8x O₁₆ H_2(9-4x)]²⁺CO₃ ^2-(also written as Ni)^II _8(1-x)Ni^III _8xO₁₆H_2(9-4x)CO₃. When x is 1, in its fully oxidized state (i.e., when it is the active material of the cathode in an energy storage device, its fully charged state), the formula of this material is Ni^III ₈O₁₆H₁₀CO₃. When x is 0, in its fully reduced state (i.e., when it is the active material of the cathode in an energy storage device, its fully discharged state), the formula of this material is Ni^II ₈O₁₆H₁₈CO₃。

In Ni^II ₈O₁₆H₁₈CO₃Deprotonation of the middle OH ion to electrode charge can be written as:

charging: ni^II ₈O₁₆H₁₈CO₃-8x H⁺-8x e^-→xNi^III ₈O₁₆H₁₀CO₃+(1-x)Ni^II ₈O₁₆H₁₈CO₃。

In Ni^III ₈O₁₆H₁₀CO₃Middle O^2-Or OH^-Ion protonation makes the electrode discharge writable:

discharging: ni^III ₈O₁₆H₁₀CO₃+8x H⁺+8x e^-→x Ni^II ₈O₁₆H₁₈CO₃+(1-x)Ni^III ₈O₁₆H₁₀CO₃。

Containing Ni in combination as described above^II-Ni^IIIElectrode and Fe of DLH^II-Fe^IIIIn an energy storage device of an electrode of DLH, the trivalent molar ratio is x { [ M { ] { [ M ]^III]/([M^II]+[M^III]) In which M^IIAnd M^IIIRespectively, a metal in a divalent and trivalent state), and, when one electrode has x ═ 1, the other electrode has x ═ 0 (and vice versa).

In such an energy storage device, which electrode will be the cathode and which will be the anode can be determined experimentally (and may depend on Ni^II-Ni^IIIDLH and Fe^II-Fe^IIIThe fermi level and brillouin zone of DLH).

If the cathode is Ni-containing^II-Ni^IIIElectrode of DLH, then the discharge of the cathode can be written as:

Ni^III ₈O₁₆H₁₀CO₃+8x H⁺+8x e^-→x Ni^II ₈O₁₆H₁₈CO₃+(1-x)Ni^III ₈O₆H₁₀CO₃。

the relevant reactions at the anode are:

Fe^II ₆O₁₂H₁₄CO₃-6x H⁺-6x e^-→x Fe^III ₆O₁₂H₈CO₃+(1-x)Fe^II ₆O₁₂H₁₄CO₃。

the charge balance is:

3Ni^III ₈O₁₆H₁₀CO₃+4Fe^II ₆O₁₂H₁₄CO₃→3x Ni^II ₈O₁₆H₁₈CO₃+3(1-x)Ni^III ₈O₆H₁₀CO₃+4x Fe^III ₆O₁₂H₈CO₃+4(1-x)Fe^II ₆O₁₂H₁₄CO₃。

thus, in the above case, the cathode is Ni^III ₈O₁₆H₁₀CO₃And the anode is Fe^II ₆O₁₂H₁₄CO₃。

On the other hand, if the cathode is Fe-containing^II-Fe^IIIElectrode of DLH, then the discharge of the cathode can be written as: fe^III ₆O₁₂H₈CO₃+6x H⁺+6x e^-→x Fe^II ₆O₁₂H₁₄CO₃+(1-x)Fe^III ₆O₁₂H₈CO₃。

The relevant reactions at the anode are:

Ni^II ₈O₁₆H₁₈CO₃-8x H⁺-8x e^-→x Ni^III ₈O₁₆H₁₀CO₃+(1-x)Ni^II ₈O₁₆H₁₈CO₃。

the charge balance is:

4Fe^III ₆O₁₆H₈CO₃+3Ni^II ₈O₁₆H₁₈CO₃→4x Fe^II ₆O₁₂H₄CO₃+4(1-x)Fe^III ₆O₁₂H₈CO₃+3x Ni^III ₈O₁₆H₁₀CO₃+3(1-x)Ni^II ₈O₁₆H₁₈CO₃。

thus, in this case, the cathode is Fe^III ₆O₁₆H₈CO₃And the anode is Ni^II ₈O₁₆H₁₈CO₃。

In some embodiments, the electrolyte in the energy storage device may be CO having a basic pH (e.g., pH 8-12 or 9-11)₃ ^2-/HCO^3-A buffering agent. In some embodiments, the pH of the buffer may be about 10. A clear advantage of using such an electrolyte is E, which is performed in order to understand the corrosion process of iron and steel_hPrevious studies of pH maps show that: the "patina" compound undergoing protonation-deprotonation is very stable at this basic pH, whereas it dissolves at pH 4. Preparation of Ni by the above coprecipitation reaction^II _8(1-x)Ni^III _8xO₁₆H_2(9-4x)CO₃The active product gives a product with a crystal size of about one tenth of a micron (e.g., 50-150nm, 75-125nm, or about 100 nm). Therefore, these crystals must be electrically connected to each other through a conductive resin to form a composite material. Graphite-containing resins (containing binder and graphite) are commonly used in all batteries on the market, including LiFePO₄And can be used for the electrodes of the present application.

The Ni mentioned above can be obtained by synthesis of a suitable double hydroxide followed by immediate oxidation by in situ deprotonation with hydrogen peroxide^II _8(1-x)Ni^III _8xO₁₆H_2(9-4x)CO₃A material. Reselecting carbonate anion CO₃ ^2-For insertion, and the ratio x { [ Ni ]³⁺]/([Ni²⁺]+[Ni³⁺]) Equal to 1/4. A kind of hydrotalcite is named as takovite and has the formula of Ni^II ₆Al^III ₂(OH)₁₆CO₃，4H₂Minerals of O are present in the natural environment and are found in nickel deposits such as new karlidonia. It has been found that this compound can pass Ni in the laboratory^IISalt and Al^IIICoprecipitation of salts. The inventors have found that Ni is present in an oxygen-free atmosphere, e.g. in a nitrogen atmosphere^IISalt and Ni^IIIAnalogous co-precipitation of salts to produce the double hydroxide compound Ni^II ₆Ni^III ₂(OH)₁₆CO₃. Immediately oxidizing the synthesized compound with sufficient hydrogen peroxide, again in an oxygen-free atmosphere (e.g., nitrogen atmosphere), to obtain a new fully oxidized compound Ni^III ₈O₁₆H₁₀CO₃. The compound can then be exposed to air without degradation. The compound can be used as a second electrode of an Fe-Ni proton battery, namely the following batteries: wherein the first electrode comprises Fe as described above^II _6(1-x)Fe^III _6xO₁₂H_2(7-3x)CO₃Compound (x is 0 to 1). The divalent state is automatically reached when the electrodes are charged (see voltammogram of fig. 1).

Can mix Ni^III ₈O₁₆H₁₀CO₃The compound is incorporated into a first graphite-based conductive resin (e.g., a resin available from Merken (Merken), formerly known as lonyland graphite, inc., and Fe^II _6(1-x)Fe^III _6xO₁₂H_2(7-3x)CO₃The compound may be incorporated into the second graphite-based conductive resin. This provides mechanical strength to the compound to form two electrodes (whose shape, volume, depth and surface are suitable for use in energy storage devices applied to, for example, electronic devices, electric vehicles, etc.). These electrodes can then be used in an energy storage device using an electrolyte that is CO with an alkaline pH (e.g., pH 8-12 or 9-11)₃ ^2-/HCO₃ ^-A buffering agent. In some embodiments, the pH of the buffer may be about 10.

Several pairs of such electrodes may be arranged in series (as in other batteries) to increase the power of the energy storage device.

Citation of publications and patent documents is not intended as an admission that any is pertinent prior art, nor does it constitute any admission as to the contents or date thereof. Those skilled in the art will recognize that the invention described herein can be practiced in various embodiments, and that the foregoing description and the following examples are for purposes of illustration and not limitation of the appended claims.

All definitions, as defined and used herein, should be understood as being controlled by dictionary definitions, definitions incorporated by reference into documents, and/or ordinary meanings of the defined terms.