A novel composite polymer electrolyte containing the lithium-ion conductor Li3Zr2Si2PO12 synthesized by cationic-exchange method for solid lithium metal batteries

The composite polymer electrolyte (CPE) is one of the most promising approaches to develop solid-state lithium metal batteries (SSLMBs) because of its easy processing, flexibility, and high ionic conductivity. In this work, NASICON-type Li3Zr2Si2PO12 (LZSP) synthesized by a skeleton-retained cationic exchange method is first introduced into poly(vinylidene fluoride) (PVDF) based polymer electrolyte. The fabricated LZSP/PVDF-CPE presents a high lithium ionic conductivity (2.28×10−4 S cm−1) at room temperature and a wide electrochemical window (> 5.2 V vs Li+/Li), which can match high-voltage cathode materials. Also, LZSP/PVDF-CPE has sufficient mechanical strength and excellent stability with lithium. For further illustration, the LiNi0.5Co0.2Mn0.3O2|LZSP/PVDF-CPE|Li SSLMBs are assembled and have achieved satisfactory cycling performance and rate stability at 25 °C, even at a wide working range within 2.8–4.5 V. Our study shows that the LZSP/PVDF-CPE is promising in solid-state lithium metal batteries.