Preparation And Performance Study Of A Flexible Battery Based On Microsphere Electrolyt

With the development of smart wearable devices,there is an urgent need for flexible energy storage systems.In this paper,a yarn-like flexible lithium-ion battery containing microsphere electrolyte was designed and prepared,The forming mechanism and electrochemical performance of microsphere electrolyte,the selection of yarn-like electrode substrate and the electrochemical performance of flexible yarn-like lithium-ion battery were discussed.Specifically,it includes the following aspects:（1）Capsule-like microsphere electrolyte of Li PF₆ liquid electrolyte encapsulated by PVDF-HFP was prepared.The results showed that the prepared microsphere electrolyte had good encapsulation effect,and there were a large number of gaps in the electrolyte,and the thermal decomposition rate of the encapsulated Li PF₆ was reduced.Microsphere electrolyte has high ionic conductivity(4.08×10^-3 S cm^-1)and high lithium-ion migration number（0.755）,and the electrochemical window is 4.1V;the microsphere electrolyte and Li Co O₂ were assembled into a semi-electrode for charge-discharge test.The battery had good performance in the first 50 cycles（the capacity retention rate was 94.5%）and excellent rate performance.（2）Through the load rate of electrode paste on copper wire,carbon fiber,PAN-carbon fiber and PPy-PAN-carbon fiber substrates and the resistance after impregnation of electrode paste,PPy-PAN-carbon fiber was finally selected as the substrate of yarn electrode,and the yarn electrode was prepared by impregnation-drying method.（3）Yarn electrode and microsphere electrolyte were assembled into yarn-like flexible lithium-ion battery,and the electrochemical impedance spectroscopy and cycle performance before and after bending were tested.The results show that the charge transfer of the battery is in both straight state and bending state.This study provides a reference for the research and development of flexible yarn lithium ion battery.