THE NOVEL IONIC TRANSFER DETECTING METHODOLOGY OF LITHIUM POLYMER BATTERY BY POSITRON ANNIHILATION STUDIES

摘要

Since the discovery of ionic conductivity in polymer-alkali salt systems two decades ago, research on ion-conductive polymers has developed in both theory and application, especially for lithium battery applications.1'2 From an application perspective, polymer electrolytes must satisfy a set of requirements for their particular purpose, including high ionic conductivity, high transport parameters, wide electrochemical stability window and compatibility with the electrode materials. Research efforts have led to the development of polymer systems that are comparable to liquid electrolytes. However, there have been fewer reports on the status of polymer electrolytes after charging and discharging. This raises a question: is ionic transport in batteries using polymer electrolytes at ambient temperatures still the same without an electrochemical reaction? According to Strauss and Ota et al, the formation of solid electrolyte interface (SEI) on cathodes can be used to improve a battery's performance.3 Therefore; we are interested in understanding the difference between polymers and liquid electrolytes by determining the ionic transport and SEI formation characteristics.