A Photo‐Assisted Calcium−Oxygen Battery Based on Dipole Heterogeneity Regulation

Calcium–oxygen (Ca–O 2 ) batteries represent an attractive energy‐storage technology that offers the potential for high energy density through reversible CaO 2 /O 2 chemistry. However, practical Ca−O 2 batteries are largely limited by the formation of an inert discharge product and intrinsically sluggish reaction kinetics, which lead to large polarization. Here, we report a rechargeable Ca–O 2 battery with an ultralow overpotential of 1.11 V via a photo‐assisted strategy based on dipole heterogeneity regulation. Dynamic light‐driven charge transport within the cell establishes favorable oxygen diffusion pathways and electrochemical reaction routes, significantly improving the transport efficiency of O 2 and charge carriers. Theoretical simulations elucidate the kinetic origin of this light‐enhanced process, revealing that regulating the reaction routes for CaO 2 formation and decomposition is effective in lowering the product‐decomposition energy barrier. The resulting photo‐assisted Ca−O 2 battery system achieves a round‐trip efficiency of 66.12% under illumination, revealing the effectiveness of the dipole‐heterogeneity‐enabled photo‐assisted strategy for Ca−O 2 electrochemistry. This work not only provides a strategy to mitigate the inherent kinetic limitations of traditional Ca–O 2 batteries but also provides insights for the development of new photo‐assisted energy storage systems.