Regulating local chemical softness of collector to homogenize Li deposition for anode-free Li-metal batteries

Regulating the surface structure of collector to synergistically reduce the nucleation and lateral growth barrier of Li⁺ electrodeposition is key to long-cycle anode-free Li-metal batteries (AFLMB), but its adjusting mechanism and modulation remains formidable challenge. Herein, a previously-unreported heterogeneous collector with hard-base sites and soft-acidity sites is proposed to enhance chemical interaction with hard-acid Li⁺ and soft-base Li nuclei, respectively. Theoretical analysis demonstrates that the addition of Co single atoms into N-C host improves to the hardness of N bases and the softness of carbon matrix. According to the results of operando microscopy and electrochemical measurement, the HBSA-Co SAs collector with controlled local chemical softness substantially reduce nucleation/growth barriers without any dendrite morphology observed. The NCM811-based Li metal cells with a high cathode area capacity of 15 mAh cm^-2 and limited lithium excess achieve a superior capacity retention rate of 98.8% after 150 cycles. This finding provides an avenue to rationally design highly efficient collector for AFLMB.