Stabilizing lithium metal anodes with bismuth oxide-coated 3D copper foams via an in situ bifunctional mediation layer

Abstract

Compared to commercial lithium-ion batteries, lithium metal batteries (LMBs) are promising as an ideal energy storage system with high energy density. However, the issues of lithium dendrite growth, instability of the solid-electrolyte interface (SEI), and volume expansion have limited the practical applications of lithium metal anodes. To address these issues, this work explores a novel bismuth oxide-coated copper foam current collector (BO@CF) through the in situ formation of a bifunctional interface mediation layer composed of Li-conducting Li₂O and lithiophilic Li₃Bi. This design enhances lithium-ion transport, reduces nucleation overpotential, and improves lithium deposition uniformity. The BO@CF‖Li half-cells can be stably cycled for 600 cycles with an average coulombic efficiency of 98.8%, and the symmetrical cells have a cycle life of up to 1800 h. The LiFePO₄-paired full cells demonstrate excellent stability and capacity retention even at high currents, providing a new method for stabilizing lithium metal anodes.