Interface defect chemistry enables dendrite-free lithium metal anodes

Lithium dendrite can cause battery failure and safety risks, which is a major obstacle for the commercial application of lithium metal anodes. Herein, an artificial protective layer with interface defects is proposed to promote the interfacial electrochemical kinetics and achieve the ultra-long electrochemical plating/stripping stability. Taking titanium oxide (TiO2) as a research object, the interfacial oxygen-deficient TiO2 coating (H-TiO2) shows the faster lithium ion diffusion kinetics compared to the pristine TiO2 layer and fresh lithium metal anode, and this interfacial defect chemistry can facilitate homogenous lithium ion flux and regulate lithium metal dendrite-free electrodeposition. Specifically, the H-TiO2 protective layer endows lithium metal anodes ultra-long cycling stability up to 1990 h at 2.0 mA cm−2 with a low overpotential of 27.5 mV. Remarkably, the artificial H-TiO2 coating improves the cycling stability (97.5 mAh g−1 after 350cycles) and rate performance (68.5 mAh g−1 at 4.0C) of full cells paired with LiFePO4 cathode. More importantly, this work opens a door for regulating lithium metal reversible electrodeposition by interface defect chemistry.