In situ-grown hierarchical Co3O4@MnO2 core-shell nanoarrays with a p-n heterointerface for ultralow-overpotential and highly reversible lithium-carbon dioxide batteries.

The development of high-performance Li-CO2 batteries (LCBs) is essential for advancing carbon-neutral energy-storage technologies. However, their practical application is still hindered by the difficulty of simultaneously achieving high discharge voltage and long-term cycling stability. Herein, we construct an insitu-grown hierarchical Co3O4@MnO2 core-shell heterostructure featuring a strong built-in electric field (BIEF) at the p-n heterointerface. The BIEF facilitates directional electron transfer from Co3O4 to MnO2, which in turn reconfigures the interfacial electronic structure and enhances the adsorption/activation of CO2 and related reaction intermediates. Meanwhile, the hierarchical core-shell architecture facilitates rapid electron/Li+ transport and improves the reversibility of Li2CO3 formation/decomposition. As a result, the optimized Co3O4@MnO2-8 cathode delivers an ultralow overpotential of 0.36 V, a high energy efficiency of 97.5%, and outstanding cycling stability over 1600 h at 0.1 mA cm-2. This work demonstrates that coupling p-n heterointerface engineering with hierarchical electrode design is an effective strategy for overcoming the kinetic limitations of LCBs.