Fast Li₂O₂ Electrochemistry Enabled by Co-N/Co (111) with Optimized Intermediate Adsorption.

The practical development of Li-O batteries (LOBs) urgently needs to explore robust cathode catalysts to boost the sluggish LiO reaction kinetics and parasitic reactions despite their theoretically high specific energy. Profound understanding of the cathode properties and the battery performance is rather critical in developing rational-designed electrocatalysts. In this study, a Co-N/Co (111) decorated N-doped hierarchical carbon framework (Co-N/Co@NHCF) is proposed as an efficient cathode in LOBs. Spectroscopic analysis coupled with experimental results suggests that the Co-N/Co (111) catalytic center can significantly reduce the battery overpotential, and meanwhile, the hierarchical carbon framework ensures rapid mass transportation and provides sufficient space to accommodate LiO deposition. Density functional theory calculations reveal that the incorporated Co (111) facet can effectively regulate the electronic distribution of N-carbon, optimize the adsorption of desirable intermediates, and eventually facilitate oxygen reduction reaction/oxygen evolution reaction kinetics. As expected, the Co-N/Co@NHCF catalyzed LOBs deliver a high discharge/charge capacity of 6.15/ 6.22 mAh cm with a columbic efficiency of 98.9%, along with a high rate cycling of 700 h at 0.3 mA cm. This work provides valuable instruction for the rational design of efficient catalysts for high-performance LOBs via optimization of the crystal structure and the adsorption of intermediates.