Accelerating the reaction kinetics of lithium-oxygen chemistry by modulating electron acceptance-donation interaction in electrocatalysts

Lithium-oxygen batteries (LOBs) have presented great promise in next-generation energy storage systems due to their high theoretical energy density. However, the sluggish deposition and decomposition kinetics of lithium peroxide (Li2O2) on the oxygen electrode inhibits the practical application of this type of novel power source. Herein, Co-doped Zn based zeolite imidazole framework (ZIF) nanosheets are elaborately designed and used as oxygen electrode catalysts to boost the performance of LOBs. The incorporation of Co rationally regulates the 3d-orbital electron occupation of Zn sites, which results in an appropriate electron acceptance-donation interaction between Zn sites and reactants, thus achieving the efficient activation of reactants. The optimized electronic structure of Zn sites is also capable of modulating the product morphology, resulting in the formation of unique rose-like Li2O2, which guarantees efficient mass and charge transfer and establishes a superior reaction interface between discharge products and electrodes. By virtue of these merits, the LOBs with the Zn0.8Co0.2 ZIF electrode deliver a high discharge/charge capacity (12 950.7/12 916.8 mA h g(-1)), low overpotential (0.92 V) and outstanding cycling stability (over 500 cycles). This work provides unique insights into the design of advanced catalysts to accelerate oxygen electrode reactions at the orbital level.

Automated summary

This study demonstrates the improved performance of lithium-oxygen batteries by using Co-doped Zn-based zeolite imidazole framework nanosheets as catalysts. The incorporation of Co allows for the regulation of electronic structure and the formation of unique product morphology, resulting in efficient mass and charge transfer.