Electroactive polymeric nanofibrous composite to drive in situ construction of lithiophilic SEI for stable lithium metal anodes

Abstract

Uncontrolled lithium dendrite growth hinders the practical application of lithium metal batteries (LMBs). Herein, we report a novel Li+ flux distributor achieved by placing an electroactive polyvinylidene fluoride/polymethyl methacrylate (PVDF/PMMA) composite nanofiber interlayer on a current collector, inducing uniform lithium deposition to mitigate the dendrite problem. Specifically, the released PMMA reacts with Li+ to form abundant C–O–Li bonds and generate in situ a stable lithiophilic PMMA-Li solid electrolyte interphase layer. Theoretical calculations reveal that polar C–F groups in the PVDF framework and lithiophilic PMMA-Li provide homo-dispersed Li+ migration pathways with low energy barriers. Consequently, uniform Li nucleation is achieved at the molecular level, resulting in ultrahigh cycling stability with dendrite-free Li deposition at 5 ​mA ​cm−2 and 5 mAh cm−2 for over 500 ​h. The PVDF/PMMA ​∼ ​Li || LiFePO4 (LFP) full cell presents an increased rate capacity of 110 mAh g−1 at 10 ​C. In addition, a soft-package battery demonstrates a high energy density of 289 ​Wh kg−1. This work provides a facile design for stable lithium metal anodes to promote the practical use of LMBs and other alkali metal batteries.