Photo-enhanced lithium oxygen batteries with defective titanium oxide as both photo-anode and air electrode

The catalysts for lithium-oxygen batteries have been researched for decades due to the huge energy storage ability. However, the sluggish catalytic performance towards the decomposition of discharge products (Li₂O₂) inspires us to utilize the photo-generated holes to overcome the obstacle. As novel energy storage device, the TiO₂ nanorod arrays on carbon textiles were well-designed and adopted as both air cathode and photo-anode for photo-assisted Li-O₂ batteries. Electrochemical data strongly demonstrate that the abundant photo-generated holes on the TiO₂ can efficiently oxidize the Li₂O₂ (the charge potential reduced from 4.31 V to 2.86 V vs Li/Li⁺). It is noted that the light illumination prompts the TiO₂ to be more defective and the generated oxygen vacancies further enhance the electron and Li⁺ migration, leading to the improved ORR performance (discharge potential at 2.85 V vs Li/Li⁺). The batteries can charge/discharge for 30 cycles with no decay and deliver the excellent rate performance.