Driving high capacity anode-free lithium metal batteries under unpressurized and lean electrolyte condition by an electron-deficient current collector

Abstract

The long-term cycling of anode-free lithium metal batteries (AF-LMBs) with a liquid electrolyte is hindered by the formation of inhomogeneous solid electrolyte interphase (SEI) on current collector and the subsequent irregular Li deposition. Here, we report the nano-window (NW) defect-enriched carbon current collector with a lowered Fermi level, which can address the critical issues. The low Fermi-level surface induces a defect-free SEI layer by alleviating electron tunneling at the interface, and leads to high Li nucleation density and lateral Li growth via Li-C orbital hybridization. DFT calculations and spectroscopic analyses elucidate that these effects are rooted in the electron deficiency of the NW defect structure. An AF-LMB employing an NCM811 cathode, NW-enriched 3D-current collector, and carbonate liquid electrolyte exhibits 90% capacity retention for over 50 cycles under unpressurized and lean electrolyte conditions. The defect chemistry presents a new design principle of tuning the electronic structure of current collectors enabling 3-dimensional Li deposition in AF-LMBs.