阅读说明：本技术 一种抑制钒基水系电池电极材料溶解的电解液添加剂及电解液 (Electrolyte additive for inhibiting dissolution of vanadium-based water-based battery electrode material and electrolyte ) 是由 陶占良 年庆舜 马陶 孙田将 郑仕兵 李海霞 梁静 陈军 于 2021-07-09 设计创作，主要内容包括：本发明公开了一种抑制钒基水系电池电极材料溶解的电解液添加剂及电解液,属于电池技术领域。所述添加剂为含氢键受体(含脂类、酰胺基、羟基、羰基或亚砜基等)的有机溶剂。将该添加剂加入水系电池电解液中,能够显著抑制钒基电极材料的溶解,提高电极材料的循环稳定性。本发明适于工业化生产,在大规模储能领域具有潜在应用前景。(The invention discloses an electrolyte additive for inhibiting dissolution of an electrode material of a vanadium-based aqueous battery and an electrolyte, and belongs to the technical field of batteries. The additive is an organic solvent containing a hydrogen bond acceptor (containing lipid, amido, hydroxyl, carbonyl or sulfoxide groups and the like). The additive is added into the aqueous battery electrolyte, so that the dissolution of the vanadium-based electrode material can be obviously inhibited, and the cycling stability of the electrode material is improved. The invention is suitable for industrial production and has potential application prospect in the field of large-scale energy storage.)

1. An electrolyte additive for inhibiting dissolution of a vanadium-based aqueous battery electrode material, characterized in that the additive is an organic solvent containing a hydrogen bond acceptor.

2. The electrolyte additive for inhibiting dissolution of an electrode material of a vanadium-based aqueous battery according to claim 1, wherein the organic solvent contains a hydrogen bond acceptor of a lipid, an amide group, a hydroxyl group, a carbonyl group, or a sulfoxide group.

3. The electrolyte additive for inhibiting dissolution of an electrode material of a vanadium-based aqueous battery according to claim 2, wherein the organic solvent is one or more of trimethyl phosphate, triethyl phosphate, formamide, ethylene glycol, glycerol, acetone, dimethyl sulfoxide, diethyl sulfoxide, or dipropyl sulfoxide.

4. An aqueous battery electrolyte, characterized in that the electrolyte comprises solvent water, an electrolyte salt and the additive according to any one of claims 1 to 3.

5. The aqueous battery electrolyte of claim 4, wherein the electrolyte salt comprises a lithium salt Li₂SO₄、LiClO₄LiCl or LiCF₃SO₃Sodium salt NaClO₄、NaNO₃、NaCl、Na₂SO₄Or NaCF₃SO₃Potassium salt KNO₃、K₂SO₄Or KCl, and Zn (CF) salt of zinc₃SO₃)₂、ZnSO₄Or Zn (CH)₃OO)₂One or more of the above; the concentration of the electrolyte salt is 0.5-2 mol/kg.

6. The aqueous battery electrolyte of claim 5 wherein the mole fraction of the electrolyte additive to the total solvent is 0.1 to 0.5.

Technical Field

The invention relates to the technical field of aqueous batteries, in particular to an electrolyte additive for inhibiting dissolution of an electrode material of a vanadium-based aqueous battery and an electrolyte.

Background

Non-renewable energy sources will gradually be replaced by renewable energy sources in the context of "2030 carbon peak-2060 carbon neutralization". However, new energy power generation represented by wind energy, solar energy and water energy is affected by factors such as geography, climate and time, so that the problem of discontinuous and unstable power output exists, power supply cannot be directly performed, an energy storage device needs to be equipped, and energy storage technology and industry are highly regarded by the country. The research and development of various novel electrochemical energy storage technologies are rapid, and mainly comprise secondary batteries, electrochemical super capacitors, fuel cells and the like. The electrochemical energy storage system is divided into an organic system and a water system according to the electrolyte, namely the adopted electrolyte is the organic electrolyte and the aqueous solution. The chemical power supply adopting an organic system has the safety problem due to the use of organic electrolyte, and has higher cost and greater environmental pollution. And the water system chemical power source can well compensate the defects.

The water-based battery has the advantages of safety, environmental protection, abundant resources, low cost and the like, and is widely concerned by researchers in recent years. However, developing electrode materials with high specific capacity and long cycle life still faces significant challenges. The vanadium-based electrode material with the layered or NASICON framework structure has a potential application prospect in a water-based ion battery due to high specific capacity. However, water molecules of strong polarity can corrode the crystal structure of the vanadium-based electrode material. The capacity of the vanadium-based electrode material is reduced, the cycle performance of the battery is negatively affected, and the problem of dissolution of the vanadium-based material needs to be solved.

Disclosure of Invention

The invention aims to solve the problem of dissolution of vanadium-based electrode materials in aqueous batteries researched at present, and provides an electrolyte additive, so that the problem of dissolution of the vanadium-based electrode materials in the aqueous batteries is obviously inhibited, the batteries still have good cycling stability under low current density, the cycle life of the batteries can be prolonged, and the storage time of the batteries can be prolonged.

The electrolyte additive for inhibiting the dissolution of the electrode material of the vanadium-based aqueous battery is an organic solvent containing a hydrogen bond acceptor. The hydrogen bond acceptor is a hydrogen bond acceptor containing a lipid group, an amide group, a hydroxyl group, a carbonyl group or a sulfoxide group. The organic solvent is one or more of trimethyl phosphate, triethyl phosphate, formamide, ethylene glycol, glycerol, acetone, dimethyl sulfoxide, diethyl sulfoxide or dipropyl sulfoxide.

The invention also provides an aqueous battery electrolyte, which comprises the following components: solvent water, electrolyte salt and additives as described above.

The electrolyte salt includes a lithium salt Li₂SO₄、LiClO₄LiCl or LiCF₃SO₃(ii) a Sodium salt NaClO₄、NaNO₃、NaCl、Na₂SO₄Or NaCF₃SO₃(ii) a Potassium salt KNO₃、K₂SO₄Or KCl; and zinc salt Zn (CF)₃SO₃)₂、ZnSO₄Or Zn (CH)₃OO)₂One or more of them. The concentration of the electrolyte salt is 0.5-2 mol/kg.

The mole fraction of the electrolyte additive in the total solvent is 0.1-0.5.

The invention has the advantages and beneficial effects that:

according to the invention, the additive capable of forming hydrogen bonds with water molecules is added to inhibit the activity of water, so that the water molecules with strong polarity are prevented from corroding the vanadium-based electrode material, and the dissolution of the vanadium-based electrode material of the water-based battery is inhibited. The method enables the vanadium-based electrode material of the water-based battery to have good cycling stability under low current density, and greatly improves the electrochemical performance of the battery. The aqueous electrolyte has the effect of inhibiting the dissolution of vanadium in the vanadium-based electrode material, and the scheme is simple and feasible.

Drawings

FIG. 1 shows the dissolution of vanadium in different electrolyte systems of example 1;

FIG. 2 is a charge-discharge curve of the aqueous full cell in example 2;

FIG. 3 is the cycle performance of the aqueous full cell of example 2;

FIG. 4 is the cycle performance of the aqueous full cell of example 3;

FIG. 5 shows the dissolution of vanadium in the different electrolyte systems of example 4.

Detailed Description

In order that the invention may be more readily understood, specific embodiments thereof will be further described with reference to the accompanying drawings, which are not to be construed as limiting the invention in any way. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Example 1

The embodiment provides an additive for inhibiting the dissolution of an electrode material of a vanadium-based water-based battery, wherein the additive is an organic solvent containing a hydrogen bond acceptor, and specifically is dimethyl sulfoxide.

The invention also provides an aqueous battery electrolyte, which comprises the following components: solvent water, electrolyte salt and additives; the electrolyte comprises the following components: the molar ratio of dimethyl sulfoxide in the total solvent composed of solvent water and additive dimethyl sulfoxide is 0.1, 0.2, 0.3, 0.4, 0.5 respectively; the electrolyte salt is sodium perchlorate. Sodium perchlorate is weighed and added into electrolyte solvent with the mol ratio of dimethyl sulfoxide to the total solvent of 0.1, 0.2, 0.3, 0.4 and 0.5 to prepare 2mol/kg of sodium perchlorate electrolyte. And to the electrolyte was added sodium vanadium phosphate powder (electrode material active material) in an amount of 0.5mg/ml, followed by standing for various days and testing the dissolution of vanadium.

For comparison, sodium vanadium phosphate powder was added to a 2mol/kg aqueous sodium perchlorate solution in an amount of 0.5mg/ml, and then left to stand for various days and tested for dissolution of vanadium.

The experimental result is shown in fig. 1, and the concentration of vanadium gradually increases along with the prolonging of the standing time of the electrolyte system without adding dimethyl sulfoxide; taking an electrolytic solution with the molar ratio of the dimethyl sulfoxide to the dimethyl sulfoxide being 0.3 as an example, the concentration of the vanadium can not be basically detected after the electrolytic solution is kept stand for 30 days.

Example 2

The electrochemical performance of the assembled full-cell of water system was tested using the 2mol/kg sodium perchlorate solution containing 0.5 mole fraction of dimethyl sulfoxide as an additive in example 1 as an electrolyte, using stable sodium titanium phosphate in a water system cell as a negative electrode, and sodium vanadium phosphate as a positive electrode.

Test results referring to fig. 2, the full cell still has a discharge capacity of 102mAh/g after 1000 cycles at a low current density of 0.2A/g.

The capacity retention rate of the full battery is as high as 81 percent after the full battery is cycled for 1000 circles under the low current density of 0.2A/g, the coulomb efficiency is close to 100 percent, and the test result is shown in figure 3.

The dissolution of the vanadium-based electrode material of the water-based battery is inhibited, so that the vanadium-based electrode material of the water-based battery has good cycling stability under low current density, and the electrochemical performance of the battery is greatly improved.

Example 3

The electrochemical performance of the assembled full-cell water system was tested using the 2mol/kg sodium perchlorate solution without additives of example 1 as electrolyte, sodium titanium phosphate as negative electrode, and sodium vanadium phosphate as positive electrode.

Test results referring to fig. 4, the full cell exhibited a significant capacity fade due to the dissolution of vanadium.

Example 4

The embodiment provides an additive for inhibiting dissolution of an electrode material of a vanadium-based water-based battery, wherein the additive is an organic solvent containing a hydrogen bond acceptor, and specifically is triethyl phosphate.

The invention also provides an aqueous battery electrolyte, which comprises the following components: solvent water, electrolyte salt and additives; the electrolyte comprises the following components: the molar ratio of triethyl phosphate in the total solvent composed of solvent water and additive triethyl phosphate is 0.1, 0.2, 0.3, 0.4 and 0.5 respectively; the electrolyte salt is lithium perchlorate. Weighing lithium perchlorate, adding the lithium perchlorate into an electrolyte solvent with the molar ratio of triethyl phosphate to the total solvent of 0.1, 0.2, 0.3, 0.4 and 0.5, and preparing 2mol/kg of lithium perchlorate electrolyte. And lithium vanadium phosphate powder (electrode material active material) was added to the electrolyte in an amount of 0.5mg/ml, followed by standing for various days and testing the dissolution of vanadium.

For comparison, lithium vanadium phosphate powder was added to a 2mol/kg aqueous solution of lithium perchlorate in an amount of 0.5mg/ml, and then allowed to stand for various days and tested for the dissolution of vanadium.

The experimental result is shown in fig. 5, and the concentration of vanadium gradually increases along with the extension of the standing time of the electrolyte system without adding triethyl phosphate; taking an electrolytic liquid system with the molar ratio of triethyl phosphate being 0.5 as an example, the system is kept still for 10 days, and the concentration of vanadium can not be basically detected.