A high-reversibility and capacity-fading-free negative-free indium-iodine battery and application thereof

Abstract

This invention discloses a highly reversible and capacity-degradation-free indium-iodine battery and its applications, relating to the field of new energy materials technology. The battery includes a negative electrode current collector, an electrolyte, a separator, a positive electrode, and a positive electrode current collector; the electrolyte is an aqueous electrolyte containing soluble indium salts. This invention selects indium ions instead of traditional zinc ions. Indium ions can achieve highly reversible deposition / dissolution behavior on the negative electrode current collector, and no dendrite formation occurs during cycling, thus significantly improving the reversibility of the negative electrode, effectively extending the battery's working life, and achieving excellent performance with no capacity degradation. Simultaneously, due to the negative electrode-free design, i.e., the negative electrode current collector does not contain a metallic indium layer in the initial state, the battery's volume and weight are significantly reduced, and the manufacturing process is significantly simplified, enhancing its practical application value.

Description

Technical Field

[0001] This invention relates to the field of new energy materials technology, and more specifically, to a highly reversible and capacity-degradable indium iodine battery without a negative electrode and its applications. Background Technology

[0002] With the continued growth in global demand for high-safety, low-cost, and long-life energy storage technologies, aqueous metal-ion batteries are becoming an important development direction for next-generation energy storage systems due to their inherent safety, environmental friendliness, and abundant resources. Among them, zinc-ion batteries have been widely studied for use in electrodeless battery structures due to their high theoretical capacity, good aqueous solution compatibility, and low redox potential. However, the zinc system still faces many inherent challenges: First, zinc anodes are prone to dendrite formation during deposition / dissolution, which may puncture the separator and cause a short circuit; second, zinc is thermodynamically unstable in aqueous electrolytes, easily undergoing hydrogen evolution side reactions, leading to electrolyte consumption and increased internal battery pressure; in addition, inert byproducts such as basic zinc sulfate are easily generated during discharge, irreversibly depositing on the electrode surface, resulting in loss of active material and capacity decay. These problems severely restrict the cycle life and practical application of electrodeless zinc-ion batteries. Therefore, there is an urgent need to develop a novel electrodeless aqueous battery system that combines high reversibility, long cycle life, and no capacity decay.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a highly reversible and capacity-degradable indium-iodine battery without a negative electrode and its applications. It achieves reversible, dendrite-free deposition of indium ions on a pure metal foil current collector without any physical / chemical pretreatment. This avoids the complex processes of metalophilic coating, alloying, or microstructure etching on the current collector surface required by traditional strategies, significantly simplifying the manufacturing process and reducing costs.

[0005] This invention is implemented as follows: In a first aspect, the present invention provides a highly reversible and capacity-degradable indium-iodine battery without a negative electrode, the battery comprising a negative electrode current collector, an electrolyte, a separator, a positive electrode, and a positive electrode current collector; The electrolyte is an aqueous electrolyte that includes a soluble indium salt; the soluble indium salt is at least one selected from indium chloride, indium iodide, indium bromide, indium sulfate, indium nitrate, indium trifluoromethanesulfonate, and indium acetate.

[0006] In an optional embodiment, the negative electrode current collector is selected from at least one of nickel foil, copper foil, titanium foil, stainless steel foil, or three-dimensional carbon-based current collector.

[0007] In an optional embodiment, the diaphragm is selected from at least one of glass fiber filter membrane, polyethylene filter membrane, cellulose filter membrane or microporous filter paper.

[0008] In an optional embodiment, the positive electrode active ingredient is selected from elemental iodine or soluble iodides.

[0009] In an optional embodiment, the positive current collector is selected from at least one of carbon paper, graphite felt, or titanium foil.

[0010] In an optional embodiment, the concentration of the electrolyte is 0.5-3.0 mol / L; And / or, the electrolyte content in the battery is ≤27 μL / cm³. 2 .

[0011] In an optional embodiment, the positive electrode is loaded onto the positive electrode current collector, and the areal loading of the iodine active material in the positive electrode is not less than 8 mg / cm³. 2 .

[0012] Secondly, the present invention provides an application of a negative electrode-free indium iodine battery in the fields of electrical appliances, energy storage devices, or electric vehicles.

[0013] In an optional implementation, the electrical appliance is an electrical appliance that uses a rechargeable battery; the energy storage device is an energy storage device based on a secondary battery.

[0014] Thirdly, the present invention provides an energy storage device, including the aforementioned negative electrode-free indium iodine battery.

[0015] The present invention has the following beneficial effects: This invention discloses a cathode-free indium-iodine battery. By selecting indium ions to replace traditional zinc ions, the reversibility of the battery is effectively improved. Indium ions can achieve highly reversible deposition / dissolution behavior on the cathode current collector, with no dendrite formation during cycling. This solves the technical problem of poor cycle life in cathode-free batteries and achieves long-term stable cycling without capacity decay. Simultaneously, this invention eliminates the need for a metallic indium cathode, significantly reducing manufacturing costs and battery size. Furthermore, this invention eliminates the need for surface modification of the cathode current collector and the addition of any functional additives to the electrolyte, further saving manufacturing costs, effectively simplifying the product manufacturing process, and improving the consistency and reliability of the battery system. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a cycle test diagram of the indium iodine coin cell without a negative electrode in Embodiment 1 of the present invention; Figure 2 This is a cycle test diagram of the indium iodine soft-pack battery without a negative electrode in Embodiment 1 of the present invention; Figure 3 This is a cycle test diagram of the indium iodine coin cell without a negative electrode in Embodiment 2 of the present invention; Figure 4 This is a cycle test diagram of the indium iodine coin cell without a negative electrode in Example 3 of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0019] The inventors discovered that existing negative electrode-free zinc-ion battery technology suffers from prominent problems such as poor negative electrode reversibility and short cycle life. To address these shortcomings, this invention, without adding any additives or modifying the current collector, successfully constructs a highly reversible negative electrode-free indium battery system solely by optimizing the electrolyte composition. This achieves an ultra-long cycle life (>2500 cycles) with no capacity decay, providing a novel path for next-generation safe, low-cost, long-cycle-life negative electrode-free aqueous energy storage systems.

[0020] Furthermore, the indium-iodine battery without a negative electrode described in this invention can achieve stable, long-cycle operation with no capacity decay without additional modification, even without using a metallic indium negative electrode. Because metallic indium is not used, the battery's size and weight are significantly reduced, while the manufacturing process is also significantly simplified, enhancing its practical application value.

[0021] Specifically, the present invention is achieved through the following technical solution: In a first aspect, the present invention provides a highly reversible and capacity-degradable indium-iodine battery without a negative electrode, the battery comprising a negative electrode current collector, an electrolyte, a separator, a positive electrode, and a positive electrode current collector; The electrolyte is an aqueous electrolyte that includes a soluble indium salt; the soluble indium salt is at least one selected from indium chloride, indium iodide, indium bromide, indium sulfate, indium nitrate, indium trifluoromethanesulfonate, and indium acetate.

[0022] Preferably, the concentration of the aqueous electrolyte is 0.5-3.0 mol / L, and can be 0.5 mol / L, 1.0 mol / L, 1.5 mol / L, 2.0 mol / L, 2.5 mol / L, or 3.0 mol / L, etc. Too high or too low a concentration of soluble salts will affect the viscosity and ionic conductivity of the electrolyte, thus affecting the battery's charge and discharge efficiency.

[0023] Furthermore, the electrolyte content in the negative electrode-free indium iodine battery is ≤27 μL / cm³. 2 By reducing the mass of inactive materials, the energy density of the battery is directly increased. Simultaneously, the reduced electrolyte usage lowers raw material costs and shortens the time required for processes such as electrolyte injection and formation, thereby improving production efficiency, reducing manufacturing costs, and enhancing the overall commercial value of the battery. This low-volume design achieves higher energy density output and better economic benefits with less electrolyte while ensuring basic cycle performance, providing direct technical support for the commercial application of electrodeless indium iodine batteries. It should be noted that the working principle of the electrodeless indium iodine battery described in this application is as follows: On the negative electrode side, during charging, indium ions in the electrolyte migrate to the surface of the negative electrode current collector under the drive of the applied voltage, are reduced and deposited as metallic indium, and an alloy layer is formed at the same time. During discharging, the metallic indium on the surface of the current collector is oxidized, stripped off in the form of indium ions and re-entering the electrolyte, while releasing electrons that flow to the positive electrode through the external circuit.

[0024] On the positive electrode side, during charging, the iodine element (I₂) loaded in the positive electrode accepts electrons and is reduced to iodide ions (I₂O₃) in the positive electrode current collector. - During discharge, iodide ions are oxidized to iodine molecules and reloaded in the positive electrode.

[0025] In common aqueous zinc battery systems, the deposition / stripping efficiency and reversibility of zinc ions on current collector surfaces such as nickel, copper, or stainless steel foils are low, leading to a significant reduction in battery cycle life. To address this issue, this application proposes an indium-iodine battery system. In this system, indium ions can achieve low overpotential deposition / stripping on unmodified nickel, copper, titanium, or stainless steel foils, forming an alloy layer. This effectively improves the deposition / stripping efficiency and reversibility of indium, significantly enhancing the cycle stability and extending the cycle life of the electrodeless battery.

[0026] In some preferred embodiments, the negative electrode current collector includes, but is not limited to, nickel foil, copper foil, titanium foil, stainless steel foil, or three-dimensional carbon-based current collector; wherein, the three-dimensional carbon-based current collector can be carbon cloth, carbon felt, or carbon paper. The negative electrode current collector undergoes no physical / chemical pretreatment, and indium ions are reversibly deposited on the pure metal foil current collector without dendrites, avoiding the complex processes of metalophilic coating, alloying, or microstructure etching on the current collector surface in traditional strategies, significantly simplifying the manufacturing process and reducing costs.

[0027] In some preferred embodiments, the diaphragm is selected from at least one of glass fiber filter membrane, polyethylene filter membrane, cellulose filter membrane or microporous filter paper.

[0028] In the embodiments of this application, the positive electrode active ingredient is selected from elemental iodine or soluble iodides, wherein soluble iodides include, but are not limited to, lithium iodide, zinc iodide, sodium iodide or potassium iodide.

[0029] Specifically, the loading of positive electrode active material onto the positive electrode current collector in this application includes the following steps: mixing elemental iodine and soluble iodide in a certain proportion, dissolving in deionized water, continuously stirring until the solid is completely dissolved, then uniformly coating the solution onto the positive electrode current collector, and drying it to obtain the final product.

[0030] Iodine (I₂) is an insulating solid, and its use as a positive electrode active material suffers from poor electron conductivity and slow reaction kinetics. In this invention, iodine is mixed with soluble iodide salts (such as lithium iodide, sodium iodide, etc.). The core objective is to convert the solid insulating iodine into highly soluble polyiodide ions, such as iodine tri- or iodine penta-ions, through a complexation reaction. The specific reaction pathway is as follows:

[0031] During this process, I - First, it combines with I2 to generate I3. - I3 - Further combining with I2 to generate I5 - This transformation fundamentally changes the form in which iodine exists: on the one hand, polyiodide ions have extremely high solubility in the electrolyte, fundamentally avoiding the residual accumulation of solid iodine on the electrode surface and effectively alleviating the electrode passivation problem; on the other hand, I3... - / I - and I5 - / I3 - The ionic conductivity of the redox pair is far superior to that of solid iodine, which can significantly improve the kinetics of the positive electrode reaction and enhance the reversibility of the electrode reaction, thereby improving the discharge capacity and rate performance of the battery.

[0032] The positive current collector is selected from at least one of carbon paper, graphite felt, or titanium foil.

[0033] Preferably, the positive electrode is loaded onto the positive electrode current collector, and the areal loading of the iodine active material in the positive electrode is not less than 8 mg / cm³. 2 .

[0034] In a second aspect of the invention, an application of a negative electrode-free indium iodide battery in the fields of electrical appliances, energy storage devices, or electric vehicles is provided.

[0035] In some preferred embodiments, the electrical appliance is an electrical appliance that uses a rechargeable battery; the energy storage device is an energy storage device based on a secondary battery.

[0036] In a third aspect of the invention, an energy storage device is provided, comprising the aforementioned negative electrode-free indium iodine battery.

[0037] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0038] Example 1 This embodiment provides a negative electrode-free indium-iodine battery, wherein the negative electrode current collector is copper foil, the electrolyte is a 0.5-3.0 mol / L indium sulfate aqueous solution, the separator is a glass fiber filter membrane, the positive electrode active material is a mixture of elemental iodine and lithium iodide, and the positive electrode current collector is carbon paper.

[0039] Its preparation method includes the following steps: S1. Disperse an appropriate amount of indium sulfate in deionized water and stir continuously at 500 rpm until the solid is completely dissolved and a clear solution is formed, thus obtaining an aqueous electrolyte of indium sulfate. S2. Activated carbon, conductive carbon black, and chitosan are mixed evenly in a ratio of 7:2:1. An appropriate amount of deionized water is added as a dispersant, and the mixture is ultrasonically stirred to obtain a slurry. The slurry is then evenly coated onto carbon paper and dried in a vacuum oven at 60 °C for 12 hours to obtain an iodine-free electrode sheet. S3. Mix elemental iodine and lithium iodide in a certain proportion and dissolve them in deionized water. Stir continuously at 500 rpm until the solid is completely dissolved and a homogeneous solution is formed. Then, add the solution dropwise onto an unloaded iodine electrode and dry at room temperature to obtain an iodine cathode with an iodine loading of not less than 8 mg / cm³. 2 ; S4. Clean the copper foil with deionized water using ultrasonic cleaning, and then dry it in a 60 °C forced-air oven for 2 hours before using it directly as a negative electrode current collector. S5. Assemble the above-mentioned copper foil negative electrode current collector, glass fiber filter membrane, indium sulfate electrolyte, and iodine positive electrode into a negative electrode-free indium-iodine battery, wherein the electrolyte volume is no more than 27 μL / cm 2 .

[0040] Testing current density: Using a CR2025 battery case for coin cell packaging, a current density of 1 A / g was employed to test the battery's charge-discharge capacity and long-cycle stability through repeated charge and discharge processes. Figure 1 As shown; As a pouch battery, it uses aluminum-plastic film encapsulation and has a capacity of 4 mA / cm². 2 The current density is used to test the battery's charge-discharge capacity and long-cycle stability through repeated charge and discharge processes, such as... Figure 2 As shown.

[0041] according to Figure 1 and Figure 2 The results show that the coin cell battery maintains a stable specific capacity with no significant decrease throughout the charge-discharge cycle after 2500 cycles at a current density of 1 A / g; the pouch cell battery maintains a stable specific capacity with no significant decrease at 4 mA / cm². 2 The capacity remained stable after 1600 current density cycles. Both systems exhibited excellent long-cycle stability and superior charge-discharge reversibility at the corresponding test currents.

[0042] Example 2 This embodiment provides a negative electrode-free indium-iodine battery, wherein the negative electrode current collector is titanium foil, the electrolyte is a 0.5-3.0 mol / L indium sulfate aqueous solution, the separator is a glass fiber filter membrane, the positive electrode active material is a mixture of elemental iodine and lithium iodide, and the positive electrode current collector is carbon paper.

[0043] Its preparation method includes the following steps: S1. Disperse an appropriate amount of indium sulfate in deionized water and stir continuously at 500 rpm until the solid is completely dissolved and a clear solution is formed, thus obtaining an aqueous electrolyte of indium sulfate. S2. Activated carbon, conductive carbon black, and chitosan are mixed evenly in a ratio of 7:2:1. An appropriate amount of deionized water is added as a dispersant, and the mixture is ultrasonically stirred to obtain a slurry. The slurry is then evenly coated onto carbon paper and dried in a vacuum oven at 60 °C for 12 hours to obtain an iodine-free electrode sheet. S3. Mix elemental iodine and lithium iodide in a certain proportion and dissolve them in deionized water. Stir continuously at 500 rpm until the solid is completely dissolved and a homogeneous solution is formed. Then, add the solution dropwise onto an unloaded iodine electrode and dry at room temperature to obtain an iodine cathode with an iodine loading of not less than 8 mg / cm³. 2 ; S4. Ultrasonically clean the titanium foil with deionized water, then dry it in a 60 °C forced-air oven for 2 hours and use it directly as a negative electrode current collector. S5. Assemble the above-mentioned titanium foil negative electrode current collector, glass fiber filter membrane, indium sulfate electrolyte, and iodine positive electrode into a negative electrode-free indium-iodine battery, wherein the electrolyte volume is no more than 27 μL / cm³. 2 .

[0044] Testing current density: Using a CR2025 battery case for coin cell packaging, a current density of 1 A / g was employed to test the battery's charge-discharge capacity and long-cycle stability through repeated charge and discharge processes. Figure 3 As shown.

[0045] according to Figure 3 The results show that the battery can stably complete 2000 charge-discharge cycles at a current density of 1 A / g. During the early cycle, the discharge specific capacity gradually increases and remains stable over a long period of time. The charge-discharge curves have a high degree of overlap, and the electrochemical reaction has good reversibility, demonstrating considerable long-term cycle stability.

[0046] Example 3 This embodiment provides a negative electrode-free indium-iodine battery, wherein the negative electrode current collector is copper foil, the electrolyte is a 0.5-3.0 mol / L indium chloride aqueous solution, the separator is a glass fiber filter membrane, the positive electrode active material is a mixture of elemental iodine and lithium iodide, and the positive electrode current collector is carbon paper.

[0047] Its preparation method includes the following steps: S1. Disperse an appropriate amount of indium chloride in deionized water and stir continuously at 500 rpm until the solid is completely dissolved and a clear solution is formed, thus obtaining an indium chloride aqueous electrolyte. S2. Activated carbon, conductive carbon black, and chitosan are mixed evenly in a ratio of 7:2:1. An appropriate amount of deionized water is added as a dispersant, and the mixture is ultrasonically stirred to obtain a slurry. The slurry is then evenly coated onto carbon paper and dried in a vacuum oven at 60 °C for 12 hours to obtain an iodine-free electrode sheet. S3. Mix elemental iodine and lithium iodide in a certain proportion and dissolve them in deionized water. Stir continuously at 500 rpm until the solid is completely dissolved and a homogeneous solution is formed. Then, add the solution dropwise onto an unloaded iodine electrode and dry at room temperature to obtain an iodine cathode with an iodine loading of not less than 8 mg / cm³. 2 ; S4. Clean the copper foil with deionized water using ultrasonic cleaning, and then dry it in a 60 °C forced-air oven for 2 hours before using it directly as a negative electrode current collector. S5. Assemble the above-mentioned copper foil negative electrode current collector, glass fiber filter membrane, indium chloride electrolyte, and iodine positive electrode into a negative electrode-free indium-iodine battery, wherein the electrolyte volume is no more than 27 μL / cm³. 2 .

[0048] Testing current density: Using a CR2025 battery case for coin cell packaging, and employing a current density of 1 A / g, the charge / discharge capacity and long-cycle stability of the battery were tested through repeated charge and discharge processes. Figure 4 As shown.

[0049] according to Figure 4 As shown, the copper foil-based indium iodine coin cell without a negative electrode, using indium chloride aqueous solution as electrolyte, completed 2500 charge-discharge cycles at a current density of 1 A / g. After initial activation, the discharge specific capacity of the battery rapidly increased and remained stable over a long period of time, with only a small fluctuation around 2000 cycles before quickly recovering. Overall, the charge-discharge reversibility was good, and it possessed excellent long-cycle stability characteristics.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A highly reversible and capacity-degradable indium-iodine battery without a negative electrode, characterized in that, The battery includes a negative electrode current collector, an electrolyte, a separator, a positive electrode, and a positive electrode current collector; The electrolyte is an aqueous electrolyte that includes a soluble indium salt; the soluble indium salt is at least one selected from indium chloride, indium iodide, indium bromide, indium sulfate, indium nitrate, indium trifluoromethanesulfonate, and indium acetate.

2. The highly reversible and capacity-degradable indium-iodine battery without a negative electrode according to claim 1, characterized in that, The negative electrode current collector is selected from at least one of nickel foil, copper foil, titanium foil, stainless steel foil, or three-dimensional carbon-based current collector.

3. The highly reversible and capacity-degradable indium-iodine battery without a negative electrode according to claim 1, characterized in that, The diaphragm is selected from at least one of glass fiber filter membrane, polyethylene filter membrane, cellulose filter membrane or microporous filter paper.

4. The highly reversible and capacity-degradable indium-iodine battery without a negative electrode according to claim 1, characterized in that, The positive electrode active ingredient is selected from elemental iodine or soluble iodides.

5. A highly reversible and capacity-degradable indium-iodine battery without a negative electrode according to claim 1, characterized in that, The positive current collector is selected from at least one of carbon paper, graphite felt, or titanium foil.

6. A highly reversible and capacity-degradable indium-iodine battery without a negative electrode according to claim 1, characterized in that, The concentration of the electrolyte is 0.5-3.0 mol / L; And / or, the electrolyte content in the battery is ≤27 μL / cm³. 2 .

7. A highly reversible and capacity-degradable indium-iodine battery without a negative electrode according to claim 1, characterized in that, The positive electrode is loaded onto the positive electrode current collector, and the areal loading of iodine active material in the positive electrode is not less than 8 mg / cm³. 2 .

8. The application of a negative electrode-free indium iodine battery as described in any one of claims 1-7 in the fields of electrical appliances, energy storage devices or electric vehicles.

9. The application according to claim 8, characterized in that, The electrical appliance is an electrical appliance that uses a rechargeable battery; the energy storage device is an energy storage device based on a secondary battery.

10. An energy storage device, characterized in that, Including any one of claims 1-7, the indium iodine battery without a negative electrode.

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