Mitigating Interfacial Issues in All-Solid-State Batteries

Abstract

All Solid-State Batteries (ASSB), by replacing liquid electrolyte with solvent-free solid electrolyte, have the potential to ultimately resolve the safety issues of Li-ion batteries (LIBs). Although inorganic lithium-ion conductors are available, their practical applications have been mainly hindered by interfacial issues, since it is very challenging to construct intimate contact between the solid electrode and solid electrolyte due to their rigidity in conventional ASSBs, leading to high polarization and low utilization of active materials. Herein, we developed a solid polymer electrolyte (SPE) that exhibits high Li+ conductivity of >1.2 mS/cm at room temperature and wide electrochemical window (~4.8 V vs. Li/Li+), and we also demonstrate a simple but effective interfacial engineering approach to mitigate the poor interfacial contact via in-situ polymerization process. The investigation revealed that the polymerization process of SPE plays a significant role in interfacial resistance between electrodes and electrolytes in large format pouch cells. Complete characterization of ASSBs with two SPE systems (in-situ polymerization vs. ex-situ polymerization) will be compared and presented, as well as the cell lifetime under galvanostatic cycling.