Kinetic insight into perovskite La0.8Sr0.2VO3 nanofibers as an efficient electrocatalytic cathode for high‐rate LiO2 batteries

Abstract

Abstract Efficient electrocatalysis at the cathode is essential for overcoming the limitations of LiO2 batteries such as poor stability and low rate capability. Herein, we systematically studied the kinetic behavior of a LiO2 battery comprising perovskite La0.8Sr0.2VO3 nanofibers formed by partial Sr‐cation doping and V cations with multiple oxidation states. Compared with undoped LaVO3 and La0.8Sr0.2VO4 nanofibers, perovskite La0.8Sr0.2VO3 nanofibers exhibited an improved capacity of 2000 mA g−1, and a 20‐times‐longer cycle life in LiO2 batteries. X‐ray photoelectron spectroscopy, electron paramagnetic resonance spectroscopy, and photoluminescence analyses revealed that the performance variations mainly originated from crystal defects, which modulate oxygen reduction/evolution kinetics. Through in situ Raman analysis, we showed that these structural defects are closely related to the oxygen reduction/evolution behavior of La0.8Sr0.2VO3 nanofibers and result in fewer parasitic reactions. This study offers insights into the potential rate capability of LiO2 batteries and related devices.

Keywords

• electrocatalysts
• La0.8Sr0.2VO3
• LiO2 battery
• nanofiber
• perovskite structure