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

Abstract

Regulating the surface structure of the 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 remain a formidable challenge. Herein, a previously unreported heterogeneous collector with hard-base sites and soft-acid sites is proposed to enhance chemical interaction with hard-acid Li⁺ and soft-base Li atoms, respectively. Theoretical analysis demonstrates that the addition of Co single atoms into the N–C host improves the hardness of N bases and the softness of the carbon matrix. According to the results of operando microscopy and electrochemical measurement, the HBSA-Co SA collector with controlled local chemical softness substantially reduces nucleation/growth barriers without any dendrite morphology. The NCM811-based Li metal cells with a high cathode area capacity of 15 mA h 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 a highly efficient collector for AFLMB.