LAUSR

Due to the unique safety qualities, solid composite polymer electrolyte (SCPE) has achieved considerable attentions to fabricate high energy density lithium metal batteries, but its overall performance still has to be improved. Herein, we develop a high lithium salt content poly(vinylidene fluoride) (PVDF) based SCPE enhanced by hexagonal boron nitride (h-BN) nanosheets, presenting perfect electrochemical performance, fast ion transport and efficient inhibition of lithium dendrite growth. The optimized SCPE (PVDF-L70-B5) could deliver high ionic conductivity (2.98 × 10-4 S cm-1), ultra-high Li+ ion transfer number (0.62), wide electrochemical stability window (5.24 V) and strong mechanical strength (3.45 MPa) at room temperature. Density functional theory (DFT) calculation further confirms that the presence of h-BN could promote the dissociation of LiTFSI and the rapid transfer of Li+ ions. As a result, the assembled symmetric Li/Li battery and asymmetric Li/LiFePO4 battery using PVDF-L70-B5 SCPEs both exhibit high reversible capacity, long-term cycle stability and high-rate performance when cycled at 60 oC or 30 oC. Our designed SCPEs will open up a new route to synthesize solid-state lithium batteries with high energy density and high safety.