Reasonable Design and Deep Insight of Efficient Integrated Photorechargeable Li-Ion Batteries by Using a Cu/CuO/Cu2S Electrode

Herein, Cu-foam-supported CuO nanowire arrays covered with Cu₂S nanosheet substrates (Cu/CuO/Cu₂S) are adopted as efficient photoelectrodes for photorechargeable lithium-ion batteries (PR-LIBs). The assembled PR-LIB exhibits remarkable solar energy conversion efficiency alongside superior lithium storage capabilities. Without an electrical power supply, the photocharged PR-LIB sustained a discharge process for 63.0 h under a constant current density of 0.05 mA cm^-2. The corresponding solar-to-electrical energy conversion efficiency is 4.50%, which is an impressive achievement among recently reported contemporary technologies. Mechanism investigation shows that the Cu/CuO/Cu₂S photogenerated carriers augment the extraction and insertion of Li⁺ according to different oxidation and reduction reactions in the charging and discharging reactions. This research delineates a refined model system and proposes innovative directions for developing efficient heterojunction photoelectrodes, significantly propelling the development of PR-LIB technology.