Gao, R.; Zhou, D.; Ning, D.; Zhang, W.; Huang, L.; Sun, F.; Schuck, G.; Schumacher, G.; Hu, Z.; Liu, X.: Probing the Self-Boosting Catalysis of LiCoO2 in Li–O2 Battery with Multiple In Situ/Operando Techniques. Advanced Functional Materials 30 (2020), p. 2002223/1-9
10.1002/adfm.202002223
Abstract:
Designing high-activity catalysts and revealing the in-depth structure–property relationship is particularly important for Li–O2 batteries. Herein, the self-boosting catalysis of LiCoO2 as an electrocatalyst for Li–O2 batteries and the investigation of its self-adjustment mechanism using in situ X-ray absorption spectroscopy and other operando characterization techniques is reported. The intercalation/extraction of Li+ in LiCoO2 not only induces the change in Co valence and modulates the electronic/crystal structure but also tunes the surface disorder degree, lattice strain, and local symmetry, which all affect the catalysis activity. In a discharge, highly ordered LiCoO2 acts as a catalyst to boost oxygen reduction reaction. During charging, the initial extraction of Li+ from LiCoO2 induces Li/oxygen vacancy and Co4+, which deforms CoO6 octahedron as well as lowers the symmetry, and accordingly promotes oxygen evolution reaction. This article offers insights into tuning the activity of catalysts for Li–O2 batteries with the intercalation/ extraction of alkali metal ions in traditional cathodes.