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 (TiO 2 ) as a research object, the interfacial oxygen-deficient TiO 2 coating (H-TiO 2 ) shows the faster lithium ion diffusion kinetics compared to the pristine TiO 2 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-TiO 2 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-TiO 2 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 LiFePO 4 cathode. More importantly, this work opens a door for regulating lithium metal reversible electrodeposition by interface defect chemistry.