Functional lithiophilic skeleton/evolving lithium sulfide artificial protective layer for dendrite-free Li metal anode

Abstract

The intrinsic high activity and skeletonless development of lithium (Li) metal have resulted in gruesome security issues, limiting the widespread use of Li metal anodes. Herein, a three-dimensional (3D) nanosheet skeleton with CuO/CuS (3D CuO/CuS-NS skeleton) is designed as the functional Li metal anode current collector. The functional skeleton’s 3D structure features a large specific surface area to reduce the local current density and inhibit dendrite growth. CuO/CuS loaded by the skeleton can be employed as lithiophilic sites to direct the uniform deposition of Li metal, according to density functional theory (DFT). Furthermore, during the first deposition, CuO/CuS can interact with Li metal to produce Li2O/Li2S, in which Li2S can act as an artificial protective layer to effectively improve the cycle stability of the cells. The dendrite-free deposition in the depositional process demonstrates that the 3D CuO/CuS-NS skeleton can achieve excellent Li metal anode stability. The Li metal anodes with 3D CuO/CuS-NS skeletons also exhibit outstanding electrochemical stability over 1000 h of long-term cycling. In full cells assembled with commercial LiCoO2 cathodes, the 3D CuO/CuS-NS skeletons exhibit good rate performance and capacity retention performance.