Thiazole-Linked Covalent Organic Framework Promoting Fast Two-Electron Transfer for Lithium-Organic Batteries

Abstract

Covalent organic frameworks (COFs) have been considered a potentially versatile electrode structure if they are made highly conductive and flexible to stabilize the redox functionality. Although conceptually plausible, COF-based electrodes have rarely satisfied high capacity, cyclability, and rate capability thus far. Incorporating thiazole moieties into the organic scaffold, it is able to fabricate pi-conjugated and crystalline organic electrodes and demonstrate the fast two-electron transfer in one step using azo functionality. The thiazole-linked COF electrode performed over 5000 cycles at 10 C and a high power density of approximate to 2800 W kg(-1) is achieved thanks to excellent chemical stability and high out-of-plane electrical conductivity. For comparison, COFs carrying beta-ketoenamine and imine linkers underperform due to the lack of structural stability. In this study, it is demonstrated that the design of linkages in the COFs is key to stabilize the redox reaction and show the basic principles of building COF electrodes for high-performance lithium-organic batteries.