Breaking the Humidity Barrier: ALD-Engineered Pt–WO3 Photoelectrode for Ultra-Stable Photo-Assisted Li–O2 Batteries

Rechargeable lithium oxygen (Li–O2) batteries are regarded as promising candidates for future energy storage systems due to their exceptionally high theoretical energy density. However, their practical implementation faces major obstacles, including high charge and discharge overpotentials and a semiopen battery structure that is highly sensitive to humidity. These factors lead to reduced efficiency and poor stability in moist air, significantly limiting real-world application. To address these challenges, a composite photoelectrode was developed by directly growing tungsten trioxide (WO3) nanoribbons on carbon paper (CP), followed by the uniform deposition of platinum nanoparticles using atomic layer deposition. Compared to WO3 photoelectrode, the resulting Pt–WO3 photoelectrode enables stable operation of photoassisted Li–O2 batteries under humid oxygen atmosphere. The batteries sustain stable operation for over 100 cycles without failure at current densities of 0.05 and 0.2 mA cm–2. Advanced characterization and theoretical calculations confirm the formation of an ohmic contact between platinum and tungsten trioxide, which promotes the separation of photogenerated electrons and holes, improves charge transfer, and facilitates the reversible formation and decomposition of lithium hydroxide (LiOH). This strategy effectively overcomes critical barriers faced by conventional Li–O2 batteries in real-world environments and provides a promising direction for the design of environmentally tolerant and photoelectrochemically efficient energy storage systems.