In-situ derived Ti3C2Tx MXene/TiO2 modified Cu foil combining abundant nucleation sites and favorable conductivity for stable lithium metal batteries

Abstract

The uneven lithium deposition on Cu current collector and poor interface stability of lithium metal/electrolyte would lead to rapid capacity decay and potential safety risks, which severely hinder the practical applications of lithium metal batteries. In this work, the in-situ derived Ti₃C₂T_x MXene/TiO₂ (labeled as MXene/TiO₂) composite with favorable lithiophilicity and conductivity is applied as modified layer on Cu foil current collector (labeled as MXene/TiO₂@Cu) to obtain the uniform and dense lithium plating. Compared with bare Cu and commercial TiO₂ nanoparticles modified Cu current collector (labeled as Nano TiO₂@Cu), the MXene/TiO₂@Cu combines abundant lithium nucleation sites and improved conductivity, which could promote uniform lithium plating and stripping at high current density and effectively avoid the generation of dead lithium or lithium dendrites. As a result, the MXene/TiO₂@Cu-based symmetric battery could stably cycle for 2000 h at high current density of 3 mA cm⁻² with capacity of 3 mAh cm⁻², and the MXene/TiO₂@Cu-Li‖LiFePO₄ full battery could maintain the high reversible capacity of 104.0 mAh g⁻¹ at 1 C after 500 cycles. This work provides an effective and novel protection strategy for Cu current collector, which is critical for the design of lithium metal batteries with favorite rate capability at high current density.