A high power density solid electrolyte based on polycaprolactone for high-performance all-solid-state flexible lithium batteries

Abstract

All-solid-state lithium batteries (ASSLBs) have been regarded as the next-generation battery technology owing to the superiority of safety, potentially high enetgy density and long cycling life. However, the slow charging limitations of ASSLBs hinder their practical applications. To tackle this issue, composite polymer electrolytes (CPEs) based on polycaprolactone (PCL) are developed to achieve satisfactroy enhancements for charging/discharging performances of ASSLBs. The addition of ceramic powder in PCL-based CPEs suppresses the crystallization of PCL and at the same time enhances the Li-ion transport behaivor. The present ASSLBs within PCL-based CPEs display excellent cycling performance with the initial discharge specific capacity of 108.2 mAh g-1, as well as good capacity retention of 75% after 500 cycles at a current density of 2 C at 55 °C. The high performance of ASSLBs is attributed to the high Li-ion transference number of 0.8 and excellent interfacial stability and wettability originated from the addition of ceramic components. It is demonstated that the PCL-based CPEs exhibit high Young's Modulus (2.8 GPa) and to the long-term cycling stability of ASSLBs. This study opens up new possibilities for the development of fast-charging batteries with an emphasis on the design of new polymer electrolytes.