Adjusting the electron configuration of MOFs-derived Ag/MnO1.1@C via electron transfer strategy to achieve a high-performance catalyst for potassium-oxygen batteries
Shuming Yu, Kedi Cai, Hao Zhao, Tan Wang, Tingting Qu, Lan Li, Jinchuang Li, Chuangang Yao, Xiaoshi Lang
Abstract
Potassium-oxygen (K-O 2 ) batteries can offer high energy density and low cost, but suffer from poor cycle life due to low efficiency and slow kinetics. Therefore, the development of efficient catalysts is the key to solve the problems. In this study, an efficient Ag/MnO 1.1 @C composite is designed as a catalytic cathode for K-O 2 batteries via calcining MnAg-MOFs precursors. The porous chain structure of the material facilitates the storage of discharge products and diffusion of oxygen, while the oxygen vacancies enhance the adsorption of O 2 and catalytic activity. Furthermore, the interfacial electron transfer between Ag and MnO 1.1 induces surface charge redistribution, facilitating improved electrochemical reaction kinetics that effectively promote both formation and decomposition of the discharge product. And then, the coupling effect between Ag and MnO further promotes the electron transfer in the K-O 2 battery, which greatly enhances the ORR and OER activities. As a result, the Ag/MnO 1.1 @C composite as an air cathode for K-O 2 batteries show a specific initial discharge capacity of 2328 mAh g −1 (200 mAh g −1 limiting capacity) and 145 stable cycles.