Atomic layer deposition-strengthened lithiophilicity of ultrathin TiO2 film decorated Cu foil for stable lithium metal anode

Uncontrolled dendrite growth hinders the applications of Li metal anode in rechargeable batteries, even if it possesses the highest energy density among anode materials. Uniform Li deposition is the key to solve this problem, but it is difficult to achieve on planar electrode surface. In this study, an ultrathin TiO2 film directly coating on a planar Cu current collector is prepared by atomic Layer deposition (ALD). The lithiophilic nature of the TiO2 film reduces the Li nucleation overpotential, ensuring uniform Li nucleation and continuous smooth Li deposition, which is hardly realized on the most commonly used lithiophobic planar Cu current collector. Consequently, a high columbic efficiency of 97.4% for 100 cycles at a current density of 1 mA cm−2 and a prolonged lifespan of symmetric and Li–LiFePO4 full cells can be achieved. This work provides a simple and effective way to stabilize Li metal anode.