Flaky and Dense Lithium Deposition Enabled by a Nanoporous Copper Surface Layer on Lithium Metal Anode

Dendritic Li growth is a detrimental killer that threatens the safe operation and wide application of rechargeable Li-metal batteries (LMBs). Tuning the nucleation and growth behavior of Li plating process is, therefore, essential to tackle the dendrite growth problem. Here, we demonstrate a flaky and dense Li growth behavior simply by creating a nanoporous Cu layer on the surface of Li metal anode. High-resolution SEM and AFM measurements reveal that the Li deposits first nucleate as nanoflakes within the pores of Cu layer, then these flakes continuously grow thicker until they fuse together and eventually evolve into an ultra-smooth and dense Li layer. Such a unique Li growth behavior is derived from the nanoporous Cu surface layer, which triggers a synergistic regulation of the electrodeposition kinetics by providing a uniformly distributed electric field, sufficiently enhanced Li+ diffusion flux, and also appropriately regulated lithium nucleation kinetics. As a result, stable cycling of the Li|Li symmetric cell and Li metal full cells (Li|LTO/LFP/NCM) can be achieved under high current densities and high deposition capacities. These findings illustrate the feasibility to tailor the Li deposition microstructure, which help to create a highly reversible, nondendritic, and safer Li metal anode for LMB applications.