Zn and Cl Coregulated MXene Catalyst Enhances Li-CO 2 Battery Reversibility

MXenes are promising cathodes for Li–CO 2 batteries owing to their high electrical conductivity and efficient CO 2 activation function. However, the effects of adsorption and electronic structures of MXene on the full life cycle of Li–CO 2 batteries have been rarely investigated. Here, we employ a coregulation approach to enhance the adsorption–decomposition of lithium carbonate (Li 2 CO 3 ) by introducing Zn and Cl surface groups onto the Ti 3 C 2 MXene (Zn–Ti 3 C 2 Cl 2 ) catalyst. The incorporation of Cl surface groups enhances Li 2 CO 3 adsorption on the MXene catalyst surface, resulting in the formation of small-sized and uniform Li 2 CO 3 . Additionally, the introduction of Zn shifts the d -band centers of titanium and promotes CO 2 evolution reaction (CO 2 ER) activity, thereby facilitating the decomposition of discharge products. As a result, the Li–CO 2 battery based on the Zn–Ti 3 C 2 Cl 2 catalyst exhibits an ultralow overpotential (0.72 V) at 200 mA g –1 and stable cycling for up to 1500 h. This work validates the efficacy of promoting reversibility in Li–CO 2 batteries by adjusting the adsorption-decomposition process.