Poly(ionic liquid)s assist diatomic catalysts in achieving highly efficient CO2 conversion in Li-CO2 batteries

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The rising CO2 emission has underscored the need for innovative approaches toward CO2 management. Li-CO2 batteries provide a promising strategy for direct CO2 fixation in energy storage devices with a high theoretical specific energy of 1876 Wh/kg, highlighting in effective CO2 management. A key challenge in Li-CO2 batteries is that the sluggish CO2 conversion including CO2 reduction reaction (CRR) and evolution reaction (CER) in cathode seriously deteriorates battery performance. In this project, we propose an integrated cathode design with combined pre-activator molecules and bidirectional atomic catalytic materials in cathode for improving CO2 conversion efficiency. Poly(ionic liquid)s (PILs) with high CO2 affinity, good compatibility to lithium salt and wide electrochemical window, are designed with amine groups as pre-activators in cathode for achieving CO2 activation before electroreduction on catalysts. The diatomic catalysts (DACs) with highly active dual metal centres and theoretical 100% atom utilization, are screened out as bidirectional catalysts for improving CRR/CER simultaneously. Such PILs-modified DACs will be 3D printed into self-supporting integrated cathode with designed open channels and interconnected conductive skeleton, to grant enough solid products support and effective transportation of CO2, Li ion and electron in cathode. Consequently, Li-CO2 batteries with long cycle life (over 1000 cycles) and high energy density (500 Wh/kg or above) will be targeted. In combination with in situ electrochemical characterizations and DFT calculations, mechanism of CO2 conversion in designed cathode will be clarified in this project. Results from this project will inspire cathode design of Li-CO2 batteries on pre-activator and catalytic conversion beyond direct electroreduction on catalysts. It will broaden the perspective on atomically dispersed catalysts and promote the development of energy storage devices accompanied by CO2 utilization.