Gel-State Polyoxyethylene Electrolytes For Lithium Metal Anode Protection

Lithium is the metal with the smallest mass and the lowest electrode potential among all the elements,so a battery composed of lithium metal has the advantages of high operating voltage and large mass specific capacity.In addition,the use of lithium anodes is expected to further increase the energy density of the existing battery systems,therefore it is of great significance to research the protection of the lithium anodes.However,during the charge-discharge process of lithium secondary batteries,lithium ions are unevenly plated and stripped on the surface of the anode to form "Lithium dendrites" and "dead Lithium",which poses a serious safety hazard.This article developed a new type of gel-state polyoxyethylene electrolyte system for protecting metallc lithium anodes,and it has been successfully applied to lithium iron phosphate lithium metal batteries and lithium-air batteries to achieve protection of lithium metal anodes.The main contents are listed as follows:1.A preparation method of a gel-state polyoxyethylene electrolyte GPE-B was introduced.Lithium symmetry batteries were assembled.The role of the electrolyte in the protection of metallic lithium anodes was deeply studied from the aspects of electrochemical performance analysis and morphology analysis.2.Lithium iron phosphate lithium metal button cells and pouch cells using the gel-state polyoxyethylene electrolyte GPE-B was successfully assembled.Experiments have shown that the batteries has excellent electrochemical performance,interface stability and safety performance.3.A novel gel-state polymer electrolyte GPE-N was prepared by compounding a gel-state polyoxyethylene electrolyte with a lithiated perfluorosulfonic acid membrane,and experiments have been conducted on lithium-air batteries.GPE-N electrolyte in lithium-air batteries can not only promote the uniform deposition of lithium to inhibit the growth of lithium dendrite,but also can inhibit the shuttle of active substances from positive side to the lithium metal anode,inhibit the side reactions,enhance the yield of lithium peroxide,improve the cycling performance of lithium-air batteries...