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

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