Research On Gel Polymer Electrolyte For Solid-state Zinc-air Batterie

With the development of portable electronic devices,solid-state zinc-air batteries have attracted more and more attention due to their high safety and high theoretical energy density.Solid-state electrolyte as a key component of the battery significantly affects the performance of the battery.Common polyvinyl alcohol(PVA)gel electrolyte has excellent film-forming,electrochemical inertness,low cost and environmental friendliness,but it has low ionic conductivity and poor water retention,which seriously affects the discharge and cycle performance of the battery.It is urgent to develop high performance solid-state electrolyte.In addition,the device structure of zinc-air battery also needs to be continuously developed to meet the requirements of practical application.In this paper,on the basis of PVA alkaline gel electrolyte,the methods of introducing additives into the gel and molecular modification on the gel surface were studied,which effectively improved the performance of solid-state electrolyte,and the application of new solid-state electrolyte in solid-state zinc-air battery was studied.The main contents of this paper are as follows:(1)Polyacrylic acid(PAA)and ultrafine cellulose fibers were added into PVA gel to prepare PVA/PAA/cellulose composite gel electrolyte(PVAA-Cellulose electrolyte)through physical crosslinking mechanism.It was found that the water retention,dimensional stability,mechanical properties and ionic conductivity of PVAA-Cellulose electrolyte were significantly improved.This composite gel system formed a large number of channels and hydrogen bond network structures,which can provide abundant ion channels.The solid-state zinc-air battery assembled with PVAA-Cellulose electrolyte exhibited excellent discharge performance and charge-discharge cycle stability.(2)Inspired by the bionic idea,PVA-Lecithin electrolyte was prepared by modifying the surface of PVA gel electrolyte with lecithin bilayer.A new solid-state zinc-air battery with built-in air electrode was designed,so that multiple batteries can be compactly integrated into a battery module of a certain scale to drive more high-power equipment.It was found that the water retention,dimensional stability,mechanical properties and ionic conductivity of the surface-modified electrolyte were significantly improved.Further study found that surface modification of the lecithin bilayer on PVA-Lecithin electrolyte can effectively inhibit the formation of oxidation by-products of zinc anode.The chargedischarge cycle stability of solid-state zinc-air battery assembled with PVA-Lecithin electrolyte was significantly improved.The results of the study provide new ideas for the development of solid-state gel electrolyte and solid-state zinc-air battery devices.