Biomimetic PVDF/LLTO composite polymer electrolyte enables excellent interface contact and enhanced ionic conductivity

摘要

Composite polymer electrolyte (CPE) with enhanced ionic conductivity, excellent flexibility and strong strength are urgently required for all-solid-state lithium metal batteries (LMBs). Inspired by the dragonfly wings that are super-lightweight and ultrathin but have excellent stability when subject to bending and twisting during flapping, we have constructed Li0.35La0.55TiO3 (LLTO) nanowires-filled polyvinylidene fluoride (PVDF). In our design, the PVDF is used to construct the ultrathin membrane, the 1D LLTO nanowires are acted as the veins to give rise to a high mechanical strength of 10 Mpa. The special design creates cellular surface of PVDF/LLTO-CPE, which guarantees the excellent flexibility as well as a good interface contact between CPE and Li anode. When evaluated as electrolyte for LiFePO4 vertical bar Li battery, the PVDF/LLTO-CPEs can suppress Li dendrites growth, and thus presents an excellent cycling stability of 140 mAh g(-1) after 200 cycles. Moreover, the flexible LiFePO4 vertical bar PVDF/LLTO-CPE vertical bar Li4Ti5O12 pouch cell delivers a satisfactory rate performance and cycle stability under folding and bending states. The excellent performances are attributed to the unique cellular structure and super mechanical strength of biomimetic PVDF/LLTO-CPE. All results show the PVDF/LLTO-CPE is a promising solid-state electrolyte for flexible electronic devices.