Redox Molecular Junction Metal-Covalent Organic Frameworks for Light-assisted CO 2 Energy Storage.

Visible-light sensitive and bi-functionally favored CO 2 reduction (CRR)/evolution (CER) photocathode catalysts that can get rid of the utilization of ultraviolet light and improve sluggish kinetics is demanded to conquer the current technique-barrier of traditional Li-CO 2 battery. Here, a kind of redox molecular junction sp 2 c metal-covalent organic framework (i.e. Cu 3 -BTDE-COF) has been prepared through the connection between Cu 3 and BTDE and can serve as efficient photocathode catalyst in light-assisted Li-CO 2 battery. Cu 3 -BTDE-COF with redox-ability, visible-light-adsorption region, electron-hole separation ability and endows the photocathode with excellent round-trip efficiency (95.2 %) and an ultralow voltage hysteresis (0.18 V), outperforming the Schiff base COFs (i.e. Cu 3 -BTDA-COF and Cu 3 -DT-COF) and majority of the reported photocathode catalysts. Combined theoretical calculations with characterizations, Cu 3 -BTDE-COF with the integration of Cu 3 centers, thiazole and cyano groups possess strong CO 2 adsorption/activation and Li + interaction/diffusion ability to boost the CRR/CER kinetics and related battery property.