Rationally tuning the oxidation state of the open active sites in Co‐based MOFs to enhance the kinetics of Li‐O <sub>2</sub> batteries
Peng Su, Xingzi Zheng, Siao Li, Jun Xu, Haomin Jiang, Qingyu Kong, Weijie Zeng, Fei Jia, Jihao Zhang, Fan Bai, Wenli Su, J. Wang, Cheng Zhang, Zhenglong Wu, Wenkai Zhang, Mengwei Yuan
Abstract
Abstract The metal triazole (MTA)‐based MOFs were found to preferentially adsorb O‐rich species, which had enhanced electrocatalytic oxygen reduction reactions (ORR) and stabilized the O‐containing species during the discharge and charge processes in Li‐O 2 battery. However, the MOFs exhibited low electron conductivity and poor electron transfer interface in the electrocatalysis, limiting the electrocatalytic activity. To address this issue, a nanocomposite with the Co‐MTA‐coated carbon nanotubes (Co‐MTA‐C) was constructed, which formed the three‐dimensional conductivity network connected with the intersecting carbon nanotube (CNT). In this composite, the electron‐rich Co‐MTA interacted with the highly conductive CNT, resulting in a charge redistribution. Optimized the electronic structure of the Co center through compositional modifications presented a high valence compared to the pure MOFs. In situ X‐ray absorption spectroscopy revealed a direct reaction of Co sites with intermediates such as LiO x , leading to the formation of nanosheet array discharge products. The battery based on optimized Co‐MTA‐C demonstrated fast kinetics and superior stability, with a low overpotential of 1.13 V, high specific capacity of 9057 mAh g −1 , and long‐term durability of 600 cycles. It provides a facile and effective strategy for enhancing the electrocatalytic performance through rational tuning of high‐conductivity substances.