Amorphous/crystalline interface synergistic catalysis: CoSₓ/MnS heterostructure for high-performance Li-CO₂ batteries

Lithium‑carbon dioxide (Li-CO₂) batteries, combining high energy density with carbon dioxide conversion capability, were recognized as a promising next-generation energy storage system. However, their practical application is still hindered by the sluggish kinetics of the carbon dioxide reduction reaction (CO₂RR) and the carbon dioxide evolution reaction (CO₂ER). Herein, a self-supporting heterostructure catalyst composed of amorphous CoS_x and crystalline MnS (a-CoSₓ/c-MnS) has been designed based on an amorphous/crystalline interface synergistic strategy. This unique interface induces strong electronic coupling and charge redistribution, which optimizes the adsorption of reaction intermediates and thereby significantly enhances the bifunctional activity for both CO₂RR and CO₂ER. Simultaneously, the three-dimensional (3D) urchin-like open architecture provides multi-level channels for electron, ion, and gas transport. The interface regulates Li₂CO₃ discharge products into a loose, porous network of blocky crystal clusters effectively, enabling easier decomposition and mitigating passivation. The Li-CO₂ battery based on the a-CoSₓ/c-MnS cathode exhibits an ultra-low overpotential of 0.22 V, a high Coulombic efficiency of 98.62% and an energy efficiency of 91.38%. Furthermore, the battery demonstrates stable cycling for over 2000 h at a limited capacity.