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.

Automated summary

An artificial protective layer with interface defects is proposed to improve the cycling stability and rate performance of lithium metal anodes. The study focuses on titanium oxide (TiO2) and demonstrates that the interfacial oxygen-deficient TiO2 coating (H-TiO2) promotes lithium ion diffusion kinetics and prevents lithium dendrite formation. The H-TiO2 protective layer enables lithium metal anodes to have ultra-long cycling stability and improves the performance of full cells paired with LiFePO4 cathode.