This concept article elucidates the significant factors affecting discharge intermediates and reaction pathways of the Li−CO₂ batteries and highlights a *Li₂O-mediated surface lithiation mechanism.

Abstract

Li−CO₂ batteries facilitate renewable energy storage in a cost-effective, eco-friendly manner. However, an inadequate understanding of their reaction mechanism severely impedes their development. Here we outline recent mechanistic advances in the discharge processes of Li−CO₂ batteries, particularly in terms of the theoretical aspect. First, the vital factors affecting the formation of discharge intermediates are highlighted, and a surface lithiation mechanism predominantly applicable to catalysts with weak CO₂ adsorption is proposed. Subsequently, the modeling of the chemical potential of Li⁺+e⁻, which is crucial for the evaluation of the theoretical limiting voltage, is detailed. Finally, challenges and future directions pertaining to the further development of Li−CO₂ are discussed. In essence, this concept article seeks to inspire future experimental and theoretical studies in advancing the development of Li−CO₂ electrochemical technology.