Silicon-carbide fiber-reinforced polymer electrolyte for all-solid-state lithium-metal batteries

Silicon carbide (SiC) with various morphologies was employed as reinforcing fillers for poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs). Specifically, the SiC nanoparticles with an average size of 5–10 µm endow a significant enhancement of the interaction between carbon atoms for the fillers and the oxygen atoms from the PEO–lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) matrix, which provides rapid transport channels for mobile Li+ and enhances the mechanical strength of SPEs. The SPEs reinforced with one-dimensional SiC nanoparticles exhibit superior Li+ conduction, good mechanical property, and uniform Li plating. Thus, a dendrite-free plating of lithium for 0.58 mAh at 0.1 mA·cm–2 and excellent cycle stability at various current densities for 250 h are achieved in Li/Li symmetric cells using SPEs electrolytes with 5.0 wt% SiC nanoparticles. Moreover, the LiFePO4/Li full cells assembled using SPEs electrolytes with 5.0 wt% SiC nanoparticles provide a capacity of 151.5 mAh·g–1 at 0.1 mA·cm–2 (55 °C), and maintained a Coulombic efficiency of 99% for 120 cycles. Graphical abstract