An Efficient MnO₂ Photocathode with an Excellent SnO₂ Electron Transport Layer for Photo‐Accelerated Zinc Ion Batteries

Abstract

Photo‐accelerated rechargeable batteries play a crucial role in fully utilizing solar energy, but it is still a challenge to fabricate dual‐functional photoelectrodes with simultaneous high solar energy harvesting and storage. This work reports an innovative photo‐accelerated zinc‐ion battery (PAZIB) featuring a photocathode with a SnO2@MnO2 heterojunction. The design ingeniously combines the excellent electronic conductivity of SnO2 with the high energy storage and light absorption capacities of MnO2. The capacity of the SnO2@MnO2‐based PAZIB is ≈598 mAh g−1 with a high photo‐conversion efficiency of 1.2% under illumination at 0.1 A g−1, which is superior to that of most reported MnO2‐based ZIB. The boosting performance is attributed to the synergistic effect of enhanced photogenerated carrier separation efficiency, improved conductivity, and promoted charge transfer by the SnO2@MnO2 heterojunction, which is confirmed by systematic experiments and theoretical simulations. This work provides valuable insights into the development of dual‐function photocathodes for effective solar energy utilization.