Multiple protective layers for suppressing Li dendrite growth and improving the cycle life of anode-free lithium metal batteries

Abstract

Anode-free lithium metal batteries (AFLMBs) have sparked considerable attention in recent years because of their potential for high energy density; however, they suffer from severe Li dendrite growth and unstable solid electrolyte interphase (SEI), which typically result in rapid capacity decay. Herein, we demonstrate a long-life anode-free pouch cell by designing a dual-coating protective layer (Cu-Sn@SFPH) electrode with Sn-coated Cu (denoted as Cu-Sn) as the bottom layer and SrF2 nanoparticles strengthened by poly (vinylidene fluoride)-co-hexafluoropropylene (PVDF-HFP) as the top layer. The in-situ formed LiF-rich SEI enables fast Li+ transfer, while the lithiophilic Li-Sn and Li-Sr alloy layers serve as nucleation seeds for uniform Li deposition. The dual-coated Cu electrode in the Cu-Sn@SFPH||Li cell exhibits remarkable cycling stability for more than 3,200 h at a capacity of 2 mAh cm−2. The NCM111||Cu-Sn@SFPH pouch cell demonstrates outstanding performance with a capacity retention of 72.1 % and an average Coulombic efficiency (CE) of 99.9 % for 120 cycles. Under practical conditions, with NCM cathodes and a lean electrolyte volume, this design strategy opens a new approach to AFLMBs.