Light Enables the Cathodic Interface Reaction Reversibility in Solid‐State Lithium‐Oxygen Batteries

Limited triple‐phase boundaries arising from the accumulation of solid discharge product(s) in solid‐state cathodes (SSCs) pose a challenge to high‐property solid‐state lithium‐oxygen batteries (SSLOBs). Light‐assisted SSLOBs have been gradually explored as an ingenious system; however, the fundamental mechanisms of the SSCs interface behavior remain unclear. Here, we discovered that light assistance can enhance the fast inner‐sphere charge transfer in SSCs and regulate the discharge products with spherical particles generated via the surface growth model. Moreover, the high photoelectron excitation and transportation capabilities of SSCs can retard cathodic catalytic decay by avoiding structural degradation of the cathode with a reduced charge voltage. The light‐induced SSLOBs exhibited excellent stability (170 cycles) with a low discharge–charge polarization overpotential (0.27 V). Furthermore, transparent SSLOBs with exceptional flexibility, mechanical stability, and multiform shapes were fabricated for theory‐to‐practical applications in sunlight‐induced batteries. Our study opens new opportunities for the introduction of solar energy into energy storage systems. Granulate‐like discharge products are randomly stacked on solid‐state cathodes (SSCs), facilitating their accommodation and ensuring the effective triple‐phase boundaries (TPBs) of SSLOBs, thereby improving the battery reversibility of light irradiation.