Photo‐Assisted Liquid Organic Cathode with Ultralow Resistance and High Diffusion Coefficient for Membrane‐Free Aqueous Zinc‐Ion Battery

Abstract Photo‐assisted battery electrodes typically rely on solid‐state metal‐ion systems, which face challenges such as low wettability and poor electrode kinetics, limiting their performance. This work introduces a significant breakthrough in photo‐assisted liquid battery technology by developing an organic liquid cathode based on azobenzene compounds dissolved in high‐polarity ether solvents. The bifunctional electrode integrates photoelectric conversion and energy storage capabilities, enabling efficient electron transfer under light illumination. Experimental results demonstrate that the liquid electrode exhibits a 62.6% higher discharge capacity under light compared to dark conditions. Additionally, the charge transfer resistance is reduced to 0.14% of that in solid‐state counterparts, while the diffusion coefficient increases by 18.62 times under dark conditions. Upon illumination, the resistance is further reduced, and the diffusion coefficient is significantly enhanced, accompanied by a notable increase in pseudocapacitive contributions. These enhancements highlight the exceptional photo‐enhanced performance of the liquid electrode. By overcoming the limitations of traditional solid‐state systems, this innovation paves the way for next‐generation energy storage solutions with superior efficiency and multifunctionality, offering promising applications in advanced energy technologies.