CN-122025805-A - Electrolyte, battery containing same and electronic equipment

Abstract

The invention relates to the technical field of electrochemical energy storage, in particular to electrolyte, a battery containing the electrolyte and electronic equipment, wherein the electrolyte comprises alkali metal salt, a solvent, a film forming additive and a redox shuttle additive, and the redox shuttle additive is 4-cyano-2, 6-tetramethyl piperidine 1-oxygen radical. The electrolyte provided by the invention can be applied to a non-negative electrode lithium/sodium metal battery to reactivate dead lithium/sodium so as to improve the utilization rate of lithium/sodium in the battery and prolong the service life of the battery.

Inventors

• ZHANG JUNWEI
• HUANG YUXI
• LIU PENG
• XU XIONGWEN

Assignees

• 湖南立方新能源科技有限责任公司
• 湖南钠方新能源科技有限责任公司

Dates

Publication Date

20260512

Application Date

20251110

Claims (11)

1. 1. An electrolyte comprising an alkali metal salt, a solvent, a film-forming additive and a redox shuttle additive, wherein the redox shuttle additive is a 4-cyano-2, 6-tetramethylpiperidine 1-oxyl radical and has the chemical structural formula shown as follows: 。
2. 2. the electrolyte of claim 1 wherein the redox shuttle additive comprises 0.1% -1% by mass of the total mass of the electrolyte.
3. 3. The electrolyte according to claim 1, wherein the alkali metal salt is a lithium salt or a sodium salt, and/or the concentration of the alkali metal salt in the electrolyte is 0.8 to 1.5mol/L.
4. 4. The electrolyte of claim 3, wherein the lithium salt comprises at least one of lithium hexafluorophosphate, lithium bis-fluorosulfonyl imide, lithium bis-trifluoromethylsulfonyl imide, and lithium perchlorate, and the sodium salt comprises at least one of sodium hexafluorophosphate, sodium bis-fluorosulfonyl imide, and sodium perchlorate.
5. 5. The electrolyte of claim 3 wherein the alkali metal salt is a lithium salt and the film forming additive comprises at least one of lithium tetrafluoroborate, lithium nitrate, lithium difluorophosphate, lithium difluorooxalato borate, hexanetrinitrile, vinylene carbonate, fluoroethylene carbonate.
6. 6. The electrolyte of claim 3 wherein the alkali metal salt is a sodium salt and the film forming additive comprises at least one of sodium tetrafluoroborate, sodium nitrate, sodium difluorophosphate, sodium difluorooxalato borate, vinylene sulfate, fluoroethylene carbonate, tris (trimethylsilane) borate, tris (trimethylsilane) phosphate.
7. 7. The electrolyte of any one of claims 1 to 6, wherein the film-forming additive comprises 2.5% to 11.5% by mass of the total mass of the electrolyte.
8. 8. The electrolyte of claim 1, wherein the solvent is an ether solvent.
9. 9. A battery comprising the electrolyte of any one of claims 1-8.
10. 10. The battery of claim 9, wherein the battery comprises at least one of a non-negative lithium metal battery, a non-negative sodium metal battery.
11. 11. An electronic device comprising the battery of claim 9 or 10.

Description

Electrolyte, battery containing same and electronic equipment Technical Field The invention relates to the technical field of electrochemical energy storage, in particular to electrolyte, a battery containing the electrolyte and electronic equipment. Background Lithium ion batteries have achieved great success in large-scale commercial applications such as electric vehicles and portable devices. However, conventional lithium ion batteries based on graphite negative electrode intercalation chemistry cannot meet the energy density requirements of various emerging fields for lithium batteries. In order to meet the urgent demands of battery systems for higher energy density, lithium metal batteries are considered as ideal candidates for replacing lithium ion batteries due to their high theoretical capacity and low potential. It is reported that replacing a graphite negative electrode in a lithium ion battery with a lithium metal negative electrode can increase the energy density by 50%. Lithium batteries have poor lithium plating/stripping performance and irreversible loss of lithium have hindered further development of lithium batteries, where excess lithium is typically used to compensate for the loss of irreversible lithium. However, the high reactivity of lithium towards organic electrolytes may lead to combustion or even explosion of the electrolyte. By avoiding the use of excess lithium to pursue a highly safe Lithium Metal Battery (LMB), a new battery configuration with zero excess lithium is facilitated, a non-negative lithium metal battery (AFLMB). Since the AFLMB does not use a lithium metal negative electrode, the safety risk caused by lithium can be effectively avoided, and the energy density is maximized. The sodium ion battery has the roles of being used as a substitute of lithium because of the advantages of abundant sodium resources, low cost, high cost performance and the like, and is getting more and more attention in the field of batteries. Lithium and sodium are similar to the group IA alkali metal elements of the periodic table in physical and chemical properties, and can be theoretically used as metal ion carriers of secondary batteries. During charging of a non-negative lithium/sodium metal battery, lithium/sodium ions are extracted from the positive electrode and deposited on the surface of the current collector, while during subsequent discharging, lithium/sodium ions are stripped from the in-situ formed lithium/sodium negative electrode and intercalated into the positive electrode. On the one hand, since the flow rate of lithium/sodium ions is not uniform, the deposited alkali metal is liable to form dendrites on the negative electrode, and the lithium/sodium stripping action occurring at the tip of dendrites will lead to the accumulation of dead lithium/sodium and be electrically isolated from the negative electrode of alkali metal, on the other hand, the unavoidable electrolyte decomposition and the formation of Solid Electrolyte Interface (SEI) film continuously consume alkali metal ions, and the consumption of lithium/sodium due to SEI formation reaction will become a serious problem in view of the high specific surface area of dendrite lithium/sodium. If there is no stable SEI film protection and excessive active lithium/sodium compensation on the negative electrode, irreversible loss of lithium/sodium ions during cycling, resulting from "dead lithium/sodium" and side reactions, will directly lead to degradation of battery capacity and reduced cycle life. Disclosure of Invention The invention provides an electrolyte, a battery and electronic equipment containing the electrolyte, and the electrolyte can reactivate dead lithium/sodium to improve the utilization rate of lithium/sodium in the battery and prolong the service life of the battery. In order to solve the technical problems, the invention adopts the following technical scheme: An electrolyte comprising an alkali metal salt, a solvent, a film forming additive and a redox shuttle additive, wherein the redox shuttle additive is a 4-cyano-2, 6-tetramethylpiperidine 1-oxyl radical and has the chemical structural formula shown as follows: 。 In some embodiments, the redox shuttle additive comprises 0.1% -1% by mass of the total mass of the electrolyte. In some embodiments, the alkali metal salt is a lithium salt or a sodium salt, and/or the alkali metal salt is present in the electrolyte at a concentration of 0.8 to 1.5mol/L. In some embodiments, the lithium salt comprises at least one of lithium hexafluorophosphate, lithium bis-fluorosulfonyl imide, lithium bis-trifluoromethylsulfonyl imide, lithium perchlorate, and the sodium salt comprises at least one of sodium hexafluorophosphate, sodium bis-fluorosulfonyl imide, sodium perchlorate. In some embodiments, the alkali metal salt is a lithium salt and the film forming additive comprises at least one of lithium tetrafluoroborate, lithium nitrate, lithium difluorophosphate, lithium