Recent Advances and Future Perspectives of PVDF-Based Composite Polymer Electrolytes for Lithium Metal Batteries: A Review

Lithium metal batteries (LMBs) using solid-state electrolytes (SSEs) can achieve dual enhancement of energy density and safety performance and have attracted considerable attention. In spite of their excellent flexibility and processability, poly(vinylidene fluoride) (PVDF)-based electrolytes, regarded as a prominent member of SSEs in LMBs, suffer from low ionic conductivity and high internal resistance. The structure of PVDF-based composite polymer electrolytes (CPEs) allows them to combine the advantages of inorganic components and PVDF substrates. The use of modification and advanced technology can achieve higher mechanical strength and improved electrochemical properties of PVDF-based CPEs, but their practical application still needs to be explored. This paper reviews recent research progress of PVDF-based CPEs in LMBs, focuses on the methods to improve the electrochemical and safety performance of PVDF-based CPEs, and specifically discusses five aspects of properties upgrading as the main line, namely, the ionic conductivity, ion migration properties, mechanical properties, thermal stability, and electrochemical stability windows. Finally, the challenges and application prospects of high-performance PVDF-based CPEs in future development are presented.