Electrolyte additive and electrolyte for high cycle life zinc-nickel battery

Abstract

The application belongs to the technical field of batteries, and particularly relates to an electrolyte additive and electrolyte for a zinc-nickel battery with a long cycle life. The electrolyte additive comprises indium oxide and a surfactant, the surfactant comprises sodium dodecyl benzene sulfonate, sodium dodecyl sulfate and a fluorine-containing anionic-nonionic amphoteric surfactant, and the fluorine-containing anionic-nonionic amphoteric surfactant is prepared by first free radical addition of perfluorohexyl ethyl iodine and allyl polyoxyethylene ether, and then sulfonation reaction of terminal hydroxyl groups of the addition product. The prepared indium oxide and surfactant have a synergistic effect in the electrolyte, and can simultaneously improve the cycle life of the zinc-nickel battery at high and low temperatures.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, specifically relating to an electrolyte additive and electrolyte for high cycle life zinc-nickel batteries. Background Technology

[0002] In recent years, Zn-Ni batteries have attracted much attention among alkaline secondary batteries with zinc as the anode due to their high operating voltage and excellent high-current charge / discharge capability. During cycling, zinc dendrite growth is one of the main reasons for the short cycle life of nickel-zinc batteries. During charging, zinc ions are unevenly deposited on the negative electrode surface, forming dendritic crystals. As the number of cycles increases, the dendrites continue to grow and may puncture the separator, leading to a short circuit. Zinc self-corrosion is another important factor affecting the cycle life of nickel-zinc batteries. In alkaline electrolytes, zinc reacts with water to produce zinc hydroxide and hydrogen gas. This process not only consumes active materials but also increases the internal pressure of the battery and changes the electrolyte composition. These issues directly affect the battery's high and low temperature performance.

[0003] Studies have shown that PEG-300, as an electrolyte additive, can form a protective film on the surface of the zinc anode, guiding the uniform deposition of zinc ions and effectively inhibiting dendrite growth. Research by Professor Zhong Cheng's team at Tianjin University indicates that introducing polyethylene glycol (PEG-300) into the electrolyte, through preferential adsorption on the zinc anode to form a protective layer, can suppress the tip effect and limit Zn(OH)4 growth. 2- Lateral diffusion. Furthermore, the long-chain molecules of PEG inhibit Zn(OH)4. 2- It diffuses from the zinc anode surface into the bulk electrolyte, thereby inhibiting self-corrosion.

[0004] Chinese patent CN117059909A discloses a zinc-nickel battery ultra-low temperature electrolyte and its preparation method. The zinc-nickel battery ultra-low temperature electrolyte includes zinc oxide and a strong alkali. The zinc-nickel battery ultra-low temperature electrolyte also contains electrolyte additives: a humectant and an antifreeze agent. The combination of dimethyl sulfoxide and polyethylene glycol in a certain proportion can effectively improve the low temperature performance of the battery, especially its performance at ultra-low temperatures.

[0005] Research has found that while existing electrolyte additives can improve battery performance at low temperatures to some extent, their performance at high temperatures is less than satisfactory. Since battery performance is equally important in both high and low temperatures, achieving a balance between the two and realizing synergistic improvement in high and low temperature performance has become a critical issue that urgently needs to be addressed. Summary of the Invention

[0006] The purpose of this invention is to provide an electrolyte additive and electrolyte for high cycle life zinc-nickel batteries.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] An electrolyte additive for high cycle life zinc-nickel batteries, the electrolyte additive comprising: indium oxide and a surfactant, the surfactant comprising sodium dodecylbenzenesulfonate, sodium dodecyl sulfate and a fluorinated anionic-nonionic amphoteric surfactant, the fluorinated anionic-nonionic amphoteric surfactant being prepared by first radically adding perfluorohexylethyl iodide and allyl polyoxyethylene ether, and then sulfonating the terminal hydroxyl group of the addition product.

[0009] Preferably, the surfactant comprises sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and a fluorinated anionic-nonionic amphoteric surfactant in a mass ratio of (1.2-1.4):1:(0.3-0.5).

[0010] Preferably, the preparation method of the fluorinated anionic nonionic amphoteric surfactant includes the following steps:

[0011] (1) Under a nitrogen atmosphere, perfluorohexyl ethyl iodide and part of di-tert-butyl peroxide were mixed, heated, and allyl polyoxyethylene ether was added dropwise. After the addition was completed, the remaining di-tert-butyl peroxide was added, the reaction was carried out, and the mixture was cooled to room temperature to obtain the addition product.

[0012] (2) Under a nitrogen atmosphere, the addition product was dissolved in anhydrous dichloromethane, cooled, and chlorosulfonic acid / dichloromethane solution was added dropwise. After the addition was completed, the temperature was raised and the reaction continued. The organic phase was separated, neutralized to neutral, washed, dried, and dichloromethane was removed by rotary evaporation. The product was then dried under vacuum to obtain a fluorinated anionic nonionic amphoteric surfactant.

[0013] This invention improves battery performance at low temperatures by using a compounded surfactant. The invention introduces anionic groups by first radically adding perfluorohexylethyl iodide and allyl polyoxyethylene ether, followed by reaction and sulfonation, to obtain a fluorinated anionic-nonionic amphoteric surfactant. This surfactant is then compounded with two other surfactants to improve interfacial kinetics at high temperatures. This significantly improves the wettability and stability of the electrode / electrolyte interface at high temperatures, reduces interfacial resistance, and inhibits zinc self-corrosion. Its extremely low surface tension allows it to adhere firmly to the interface even at high temperatures, maintaining a superhydrophilic surface. During high-rate discharge, the polarization voltage is lower, meaning that the battery has a larger effective operating voltage window during high-temperature, high-current discharge, releasing more capacity and thus increasing the capacity percentage.

[0014] Preferably, the electrolyte additive has a mass percentage of 0.2-0.4% in the electrolyte.

[0015] Preferably, the indium oxide has a mass percentage of 0.1-0.2% in the electrolyte.

[0016] Preferably, the surfactant has a mass percentage of 0.1-0.2% in the electrolyte.

[0017] Preferably, the indium oxide comprises indium oxide A, indium oxide B, and indium oxide C; the indium oxide A has a particle size of 10-40 nm, an average particle size of 30 nm, and a specific surface area of ​​20-30 m². 2 / g; Indium oxide B has a particle size of 80-150nm, an average particle size of 100nm, and a specific surface area of ​​8-15m² / g; Indium oxide C has a particle size of 0.5-1.0μm, an average particle size of 800nm, and a specific surface area of ​​2-5m² / g.

[0018] Preferably, the indium oxide comprises indium oxide A, indium oxide B and indium oxide C in a mass ratio of (0.4-0.6):(1.3-1.6):(0.8-1.0).

[0019] The study "The Influence of Electrolyte Additives on Sealed Zinc-Nickel Batteries" found that adding indium oxide to the electrolyte can improve battery performance at room temperature. However, the inventors discovered that adding indium oxide of a single particle size was not effective in improving battery performance at low temperatures. This invention improves the low-temperature performance of batteries by adding indium oxide of a specific particle size compounded with specific surfactants to the electrolyte. Analysis shows that the compound structure ensures that the catalytic interface maintains the largest, most stable, and most accessible active area in low-temperature, high-viscosity electrolytes, allowing for continuous and efficient operation. Simultaneously, under these conditions, the compounded surfactants better optimize physical transport and the interfacial environment, ensuring that the catalytic sites of indium oxide can be fully and rapidly utilized. Furthermore, the presence of indium oxide allows the excellent interface created by the surfactants to be efficiently converted into battery performance output. These two factors complement each other, jointly overcoming the kinetic barriers at low temperatures, thereby significantly improving the battery's low-temperature discharge capacity retention, rate performance, and cycle life.

[0020] An electrolyte comprising the aforementioned electrolyte additive.

[0021] Preferably, the electrolyte comprises the following components by mass percentage: 30-40% alkali, 8-12% ZnO, 0.1-0.2% indium oxide, 0.1-0.2% surfactant, and the balance being water.

[0022] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0023] 1. This invention provides an electrolyte additive and electrolyte for high-cycle-life zinc-nickel batteries, aiming to overcome the core bottleneck of current zinc-nickel batteries in wide-temperature-range applications. In practical applications, such as electric vehicles, energy storage systems, and portable power supplies in extreme climates, batteries often need to withstand both extreme cold and high temperatures. Traditional electrolyte systems struggle to balance high and low temperature performance: at low temperatures, ionic conductivity drops sharply and reaction kinetics stagnate; at high temperatures, zinc anode corrosion and hydrogen evolution side reactions are exacerbated. This trade-off severely restricts the practical application of zinc-nickel batteries. This invention, through the rational design of an electrolyte additive system, achieves synergistic regulation of high and low temperature performance at the molecular and interface levels, enabling the battery to maintain high capacity retention and stable cycle capability within a range of -40℃ to 40℃. This breakthrough not only significantly expands the applicable boundaries of zinc-nickel batteries but also provides key technical support for the commercialization of low-cost, high-safety aqueous secondary batteries in large-scale energy storage and special power supply fields, possessing significant engineering value and industrial significance.

[0024] 2. This invention significantly improves the electrochemical performance of zinc-nickel batteries in low-temperature environments by introducing a compound surfactant, solving practical problems such as difficult low-temperature start-up and rapid capacity decay. In cold regions or winter outdoor use scenarios, traditional zinc-nickel batteries often experience a sharp decline in discharge capacity, or even fail to function properly, due to increased electrolyte viscosity and hindered zinc ion migration. The compound surfactant used in this invention can form a dynamic and flexible interfacial adsorption layer on the zinc anode surface, effectively reducing interfacial tension, promoting uniform diffusion and deposition of zinc ions, and inhibiting localized concentrated growth of dendrites at low temperatures. Simultaneously, this interfacial layer can also reduce electrode polarization and increase charge transfer rate, enabling the battery to maintain a high capacity even at -40°C. This improvement has significant practical implications for promoting the application of zinc-nickel batteries in key areas such as communication base stations in high-altitude and cold regions, polar scientific research equipment, and winter emergency power supplies, significantly enhancing their environmental adaptability and reliability.

[0025] 3. This invention innovatively introduces composite indium oxide nanoparticles of specific particle sizes into the electrolyte in synergistication with customized surfactants, constructing a multifunctional composite additive system that combines conductivity, stability, and interface regulation capabilities, thereby systematically improving the low-temperature performance of the battery. Indium oxide itself has excellent electronic / ionic conductivity, and particles of specific nanoscales can be uniformly dispersed in the electrolyte. During charge and discharge, they migrate to the surface of the zinc anode, forming a conductive network and effectively reducing charge transfer impedance at low temperatures. More importantly, by combining with specific types of surfactants, not only is the dispersion stability of indium oxide improved, but the electrode / electrolyte interface structure is also synergistically optimized, suppressing zinc dendrites and reducing side reactions. This strategy significantly improves the rate performance and cycle stability of the battery at low temperatures without sacrificing high-temperature performance. This technical approach provides a new paradigm for developing wide-temperature-range high-performance aqueous batteries and has profound practical significance for achieving independent control in strategic fields such as green energy storage and special power supplies in my country. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Perfluorohexylethyl iodide, CAS: 2043-57-4. Allyl polyoxyethylene ether, APEG-500, Haian Petrochemical Plant, Jiangsu Province.

[0028] Example 1

[0029] This embodiment provides an electrolyte additive for high cycle life zinc-nickel batteries. The electrolyte additive includes indium oxide and a surfactant. The surfactant includes sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and a fluorinated anionic nonionic amphoteric surfactant in a mass ratio of 1.3:1:0.4.

[0030] The preparation method of the fluorinated anionic nonionic amphoteric surfactant includes the following steps:

[0031] (1) Under a nitrogen atmosphere, 0.28 mol of perfluorohexyl ethyl iodide and 1.0 g of di-tert-butyl peroxide were mixed, the rotation speed was controlled at 300 rpm, the oil bath temperature was raised to 140 °C, and 0.28 mol of allyl polyoxyethylene ether was added dropwise. The addition was completed uniformly within 2 h. After the addition was completed, 0.5 g of di-tert-butyl peroxide was added, and the reaction was carried out at 145 °C for 3 h. The mixture was then cooled to room temperature to obtain the addition product.

[0032] (2) Under a nitrogen atmosphere, 100g of the addition product from step (1) was dissolved in 200mL of anhydrous dichloromethane. The solution was cooled to 5°C, and a chlorosulfonic acid / dichloromethane solution (mixing ratio 1:2, v / v) was added dropwise. The amount of chlorosulfonic acid was 29.1g. The temperature during the dropwise addition was 5°C, and the dropwise addition time was 2h. After the dropwise addition was completed, the temperature was naturally raised to 25°C, and the reaction was continued for 4h. The reaction solution was poured into 200g of ice water and stirred for 30min. The solution was then transferred to a separatory funnel, and the organic phase was separated. The aqueous phase was back-extracted with 50mL of dichloromethane. The organic phases were combined, cooled to 2°C, and neutralized to neutrality with 30wt% NaOH aqueous solution. The organic phase was then separated, washed with 50mL of saturated saline solution, and anhydrous... The product is dried, filtered to remove the desiccant, and then subjected to rotary evaporation to remove dichloromethane. After vacuum drying, a fluorinated anionic nonionic amphoteric surfactant is obtained.

[0033] The indium oxide comprises indium oxide A, indium oxide B, and indium oxide C in a mass ratio of 0.5:1.5:1.0; the indium oxide A has a particle size of 10-40 nm, an average particle size of 30 nm, and a specific surface area of ​​20-30 m². 2 / g; Indium oxide B has a particle size of 80-150nm, an average particle size of 100nm, and a specific surface area of ​​8-15m² / g; Indium oxide C has a particle size of 0.5-1.0μm, an average particle size of 800nm, and a specific surface area of ​​2-5m² / g. Source: Zhejiang Manli Nanotechnology Co., Ltd.

[0034] This embodiment provides an electrolyte comprising the following components by mass percentage: 35% alkali (sodium hydroxide:potassium hydroxide mass ratio 2:1), 10% ZnO, 0.12% indium oxide, 0.18% surfactant, and the balance being water.

[0035] Example 2

[0036] This embodiment provides an electrolyte additive for high cycle life zinc-nickel batteries. The electrolyte additive includes indium oxide and a surfactant. The surfactant includes sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and a fluorinated anionic nonionic amphoteric surfactant in a mass ratio of 1.2:1:0.5.

[0037] The preparation method of the fluorinated anionic nonionic amphoteric surfactant includes the following steps:

[0038] (1) Under a nitrogen atmosphere, 0.28 mol of perfluorohexyl ethyl iodide and 1.0 g of di-tert-butyl peroxide were mixed, the rotation speed was controlled at 300 rpm, the oil bath temperature was raised to 140 °C, and 0.28 mol of allyl polyoxyethylene ether was added dropwise. The addition was completed uniformly within 2 h. After the addition was completed, 0.5 g of di-tert-butyl peroxide was added, and the reaction was carried out at 145 °C for 3 h. The mixture was then cooled to room temperature to obtain the addition product.

[0039] (2) Under a nitrogen atmosphere, 100g of the addition product from step (1) was dissolved in 200mL of anhydrous dichloromethane. The solution was cooled to 5°C, and a chlorosulfonic acid / dichloromethane solution (1:2 v / v) was added dropwise. The amount of chlorosulfonic acid was 29.1g. The temperature during the dropwise addition was 5°C, and the dropwise addition time was 2h. After the dropwise addition was completed, the temperature was naturally raised to 25°C, and the reaction was continued for 4h. The reaction solution was poured into 200g of ice water and stirred for 30min. The solution was then transferred to a separatory funnel, and the organic phase was separated. The aqueous phase was back-extracted with 50mL of dichloromethane. The organic phases were combined, cooled to 2°C, and neutralized to neutrality with 30wt% NaOH aqueous solution. The organic phase was then separated, washed with 50mL of saturated saline solution, and anhydrous... The product is dried, filtered to remove the desiccant, and then subjected to rotary evaporation to remove dichloromethane. After vacuum drying, a fluorinated anionic nonionic amphoteric surfactant is obtained.

[0040] The indium oxide comprises indium oxide A, indium oxide B, and indium oxide C in a mass ratio of 0.4:1.6:0.8; the indium oxide A has a particle size of 10-40 nm, an average particle size of 30 nm, and a specific surface area of ​​20-30 m². 2 / g; Indium oxide B has a particle size of 80-150nm, an average particle size of 100nm, and a specific surface area of ​​8-15m² / g; Indium oxide C has a particle size of 0.5-1.0μm, an average particle size of 800nm, and a specific surface area of ​​2-5m² / g.

[0041] This embodiment provides an electrolyte comprising the following components by mass percentage: 35% alkali (sodium hydroxide:potassium hydroxide mass ratio 2:1), 10% ZnO, 0.12% indium oxide, 0.18% surfactant, and the balance being water.

[0042] Comparative Example 1

[0043] The difference between this comparative example and Example 1 is that the surfactant includes sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and octadecyltrimethylammonium chloride in a mass ratio of 1.2:1:0.5.

[0044] Comparative Example 2

[0045] The difference between this comparative example and Example 1 is that the surfactant includes sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium methylene dinaphthalenesulfonate in a mass ratio of 1.2:1:0.5.

[0046] Comparative Example 3

[0047] The difference between this comparative example and Example 1 is that the surfactant includes sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and Triton X-100 in a mass ratio of 1.2:1:0.5.

[0048] Comparative Example 4

[0049] The difference between this comparative example and Example 1 is that the fluorinated anionic-nonionic amphoteric surfactant is replaced with a nonionic surfactant. The preparation method includes the following steps: Under a nitrogen atmosphere, 0.28 mol of perfluorohexyl ethyl iodide and 1.0 g of di-tert-butyl peroxide are mixed, the rotation speed is controlled at 300 rpm, the oil bath temperature is raised to 140°C, and 0.28 mol of allyl polyoxyethylene ether is added dropwise. The addition is completed uniformly within 2 hours. After the addition is completed, 0.5 g of di-tert-butyl peroxide is added, and the reaction is carried out at 145°C for 3 hours. After cooling to room temperature, the mixture is distilled under reduced pressure to obtain the nonionic surfactant.

[0050] Comparative Example 5

[0051] The difference between this comparative example and Example 1 is that the indium oxide comprises indium oxide A, indium oxide B, and indium oxide C in a mass ratio of 1:0.5:1.5; the indium oxide A has a particle size of 10-40 nm, an average particle size of 30 nm, and a specific surface area of ​​20-30 m². 2 / g; Indium oxide B has a particle size of 80-150nm, an average particle size of 100nm, and a specific surface area of ​​8-15m² / g; Indium oxide C has a particle size of 0.5-1.0μm, an average particle size of 800nm, and a specific surface area of ​​2-5m² / g.

[0052] Comparative Example 6

[0053] The difference between this comparative example and Example 1 is that the indium oxide comprises indium oxide B and indium oxide C in a mass ratio of 1.5:1.0; the indium oxide B has a particle size of 80-150 nm, an average particle size of 100 nm, and a specific surface area of ​​8-15 m² / g; the indium oxide C has a particle size of 0.5-1.0 μm, an average particle size of 800 nm, and a specific surface area of ​​2-5 m² / g.

[0054] Comparative Example 7

[0055] This comparative example is the electrolyte of Example 5 in Chinese Patent CN117059909A, which discloses an ultra-low temperature electrolyte for zinc-nickel batteries and its preparation method.

[0056] Performance testing

[0057] A zinc anode and a nickel hydroxide cathode are used to form the battery electrode assembly. After the electrode assembly is installed in the casing, the electrolytes of Examples 1-2 and Comparative Examples 1-7 are added, and the battery is sealed. The positive and negative electrode capacity ratio of the sealed battery is 1:2.5, and the battery design capacity is 500mAh.

[0058] (1) Charge at 25℃ using the standard method: Let stand at room temperature for 1 hour, then discharge to the cutoff voltage at different rates of current, and calculate the percentage of the discharged capacity to the 0.2C discharge capacity at room temperature: 2C discharge capacity at room temperature ÷ 0.2C discharge capacity at room temperature × 100%;

[0059] (2) After standing at -40℃ for 20 hours, discharge to the cutoff voltage at different current rates and calculate the percentage of the discharged capacity to the 0.2C discharge capacity at room temperature: 2C discharge capacity at -40℃ ÷ 0.2C discharge capacity at room temperature × 100%;

[0060] (3) After standing at 40℃ for 20h, discharge to the cutoff voltage at different current rates and calculate the percentage of the discharged capacity to the 0.2C discharge capacity at room temperature: 2C discharge capacity at 40℃ ÷ 0.2C discharge capacity at room temperature × 100%;

[0061] The results are shown in Table 1.

[0062] Table 1 Performance Test Results

[0063] Percentage of continuous discharge at room temperature and 2C -40℃, 2C continuous discharge percentage 40℃, 2C continuous discharge ratio Example 1 98.7 76.2 71.0 Example 2 98.3 75.5 70.3 Comparative Example 1 95.8 64.7 60.5 Comparative Example 2 95.6 62.1 59.4 Comparative Example 3 96.0 65.4 62.9 Comparative Example 4 96.5 67.3 61.7 Comparative Example 5 96.3 66.8 60.6 Comparative Example 6 95.1 63.9 58.2 Comparative Example 7 95.6 69.3 50.1

[0064] As shown in Table 1, the electrolytes of Examples 1-2 exhibit high performance at both high and low temperatures after the addition of specific additives, which is significantly better than existing products. The results show that although the existing products of Comparative Example 7 show better performance at low temperatures, their performance at high temperatures is poor, and they cannot achieve simultaneous improvement in both high and low temperature performance.

[0065] Comparative Examples 1-4 show that changing the composition and ratio of surfactants decreases battery performance. Comparative Examples 5-6 show that changing the ratio and composition of indium oxide also decreases battery performance; only specific surfactants and indium oxide can simultaneously improve the high and low temperature performance of the battery.

[0066] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An electrolyte additive for high cycle life zinc-nickel batteries, characterized in that, The electrolyte additive includes 0.1-0.2% indium oxide and 0.1-0.2% surfactant by mass. Surfactants include sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and fluorinated anionic-nonionic amphoteric surfactants in a mass ratio of (1.2-1.4):1:(0.3-0.5). Fluorinated anionic-nonionic amphoteric surfactants are prepared by first radical addition of perfluorohexyl ethyl iodide and allyl polyoxyethylene ether, and then sulfonating the terminal hydroxyl groups of the addition product. The preparation method of fluorinated anionic nonionic amphoteric surfactants includes the following steps: (1) Under a nitrogen atmosphere, perfluorohexyl ethyl iodide and part of di-tert-butyl peroxide were mixed, heated, and allyl polyoxyethylene ether was added dropwise. After the addition was completed, the remaining di-tert-butyl peroxide was added, the reaction was carried out, and the mixture was cooled to room temperature to obtain the addition product. (2) Under a nitrogen atmosphere, the addition product was dissolved in anhydrous dichloromethane, cooled, and chlorosulfonic acid / dichloromethane solution was added dropwise. After the addition was completed, the temperature was raised and the reaction continued. The organic phase was separated, neutralized to neutral, washed, dried, rotary evaporated, and vacuum dried to obtain a fluorinated anionic nonionic amphoteric surfactant. Indium oxide comprises indium oxide A, indium oxide B, and indium oxide C in a mass ratio of (0.4-0.6):(1.3-1.6):(0.8-1.0); wherein the indium oxide A has a particle size of 10-40 nm, an average particle size of 30 nm, and a specific surface area of ​​20-30 m². 2 / g; Indium oxide B has a particle size of 80-150nm, an average particle size of 100nm, and a specific surface area of ​​8-15m². 2 / g; Indium oxide C has a particle size of 0.5-1.0 μm, an average particle size of 800 nm, and a specific surface area of ​​2-5 m² / g. 2 / g.

2. The electrolyte additive for high cycle life zinc-nickel batteries according to claim 1, characterized in that, The electrolyte additive has a mass percentage of 0.2-0.4% in the electrolyte.

3. An electrolyte comprising the electrolyte additive according to any one of claims 1-2, characterized in that, The electrolyte comprises an alkali, ZnO, indium oxide, a surfactant, and water.

4. The electrolyte according to claim 3, characterized in that, The electrolyte comprises the following components by mass percentage: 30-40% alkali, 8-12% ZnO, 0.1-0.2% indium oxide, 0.1-0.2% surfactant, and the balance being water.