Development of polycarbonate-based electrolytes with in situ polymerized electrolyte interlayers for lithium-metal batteries

Solid polymer electrolytes (SPEs), especially polycarbonate-based SPEs, have emerged as promising candidates for next-generation lithium-metal batteries (LMBs) due to their enhanced safety features and suitable mechanical and electrochemical properties. However, the limited interface compatibility between SPEs and electrodes, along with the persistent issue of lithium dendrite formation, hindered the progress of LMBs. In this study, an innovative approach is introduced to address these challenges by incorporating an in situ polymerized poly(vinyl ethylene carbonate) (PVEC) electrolyte interlayer between poly(ethylene carbonate) (PEC)-based SPE and electrode material. Furthermore, lithium nitrate (LiNO3) is incorporated as an additive in the PEC-based SPE to facilitate the formation of a stable and suitable solid electrolyte interphase (SEI) layer, thereby enhancing the cycling stability of LMBs. Notably, the Li||Li symmetric cell, equipped with the in situ PVEC electrolyte interlayer and the LiNO3-additive-containing PEC-based electrolyte, exhibited remarkable stability, maintaining a continuous cycling for 70 h at a current density of 0.1 mA cm−2. Similarly, a Li||LiFePO4 cell demonstrated impressive performance, sustaining 40 charge-discharge cycles at a current density of 0.1C (1C = 170 mA g−1) while maintaining a discharge capacity of approximately 150 mAh g−1. This work showcases a straightforward strategy for enhancing interfacial compatibility through in situ polymerization of the interlayer and the incorporation of electrolyte additives.