Covalent organic frameworks with Ni-Bis(dithiolene) and Co-porphyrin units as bifunctional catalysts for Li-O2 batteries

Si-Wen Ke; Wei Li; Yuming Gu; Jian Su; Yifan Liu; Shuai Yuan; Jing-Lin Zuo; Jing Ma; Ping He

doi:10.1126/sciadv.adf2398

Covalent organic frameworks with Ni-Bis(dithiolene) and Co-porphyrin units as bifunctional catalysts for Li-O₂ batteries

Sci Adv. 2023 Feb 3;9(5):eadf2398. doi: 10.1126/sciadv.adf2398. Epub 2023 Feb 1.

Authors

Si-Wen Ke¹, Wei Li², Yuming Gu¹, Jian Su¹, Yifan Liu¹, Shuai Yuan¹, Jing-Lin Zuo¹, Jing Ma¹, Ping He²

Affiliations

¹ State Key Laboratory of Coordination Chemistry, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China.
² Center of Energy Storage Materials & Technology, College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, National Laboratory of Solid State Microstructures, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210023, P. R. China.

Abstract

The rational design of efficient and stable catalysts for the oxygen reduction reaction and oxygen evolution reaction (ORR/OER) is the key to improving Li-O₂ battery performance. Here, we report the construction of ORR/OER bifunctional cathode catalysts in a covalent organic framework (COF) platform by simultaneously incorporating Ni-bis(dithiolene) and Co-porphyrin units. The resulting bimetallic Ni/Co-COF exhibits high surface area, fairly good electrical conductivity, and excellent chemical stability. Li-O₂ batteries with the Ni/Co-COF-based cathode show a low discharge/charge potential gap (1.0 V) and stable cycling (200 cycles) at a current density of 500 mA g^-1, rivaling that of PtAu nanocrystals. Density functional theory computations and control experiments using nonmetal or single metal-based isostructural COFs reveal the critical role of Ni and Co sites in reducing the discharge/charge overpotentials and regulating the Li₂O₂ deposition. This work highlights the advantage of bimetallic COFs in the rational design of efficient and stable Li-O₂ batteries.