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

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 Li 0.35 La 0.55 TiO 3 (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 LiFePO 4 |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 LiFePO 4 |PVDF/LLTO-CPE|Li 4 Ti 5 O 12 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.