2-Mercaptobenzimidazole-Modified Copper Foil for Regulating Lithium Deposition in Anode-Free Lithium Batteries

High Resolution Image Download MS PowerPoint Slide Anode-free lithium batteries are limited by irreversible lithium loss and unstable lithium deposition on Cu current collectors. Herein, Cu foil was modified by a simple wet-chemical treatment using 2-mercaptobenzimidazole (MBI) to regulate the Cu/electrolyte interface. X-ray photoelectron spectroscopy suggests that MBI is anchored on the Cu surface through Cu–S and Cu–N interactions, while atomic force microscopy and Kelvin probe force microscopy show that the modification changes the surface roughness and surface potential of Cu foil. Electrochemical measurements show that MBI Cu exhibits a lower lithium nucleation overpotential (26.6 mV), a higher exchange current density (1.64 mA cm –2 ), and reduced interfacial kinetic barriers compared with Bare Cu. In Li∥Cu half cells, MBI Cu also shows improved plating/stripping reversibility, slower impedance growth, and more compact lithium deposits. In anode-free Cu∥LiFePO 4 full cells, MBI Cu delivers an initial discharge capacity of 119.03 mAh g –1 and retains 49.15% of its capacity after 100 cycles, whereas the Bare Cu counterpart retains 20.71% under the same conditions. These results suggest that MBI modification is a simple molecular approach for improving interfacial stability and regulating lithium deposition on Cu current collectors in anode-free lithium batteries.