Covalent organic frameworks with Ni-Bis(dithiolene) and Co-porphyrin units as bifunctional catalysts for Li-O<sub>2</sub> batteries.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36724229.
- Also identified by DOI 10.1126/sciadv.adf2398 and PMC identifier 9891699.
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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-O<sub>2</sub> 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-O<sub>2</sub> 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<sup>-1</sup>, 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 Li<sub>2</sub>O<sub>2</sub> deposition. This work highlights the advantage of bimetallic COFs in the rational design of efficient and stable Li-O<sub>2</sub> batteries.