Photoinduced homogeneous RuO2 nanoparticles on TiO2 nanowire arrays: A high-performance cathode toward flexible Li-CO2 batteries

Rechargeable Li-CO2 battery as a CO2 utilization and conversion device has attracted worldwide attention in recent years due to its high energy density and environmental friendliness. However, its practical utilization is primarily hindered by unsatisfactory electrochemical performances (such as high over-potential, low capacity, and poor cycle life), mainly caused by the insulating/insoluble discharge product, Li2CO3. Herein, a free-standing cathode of RuO2 nanoparticles decorated on TiO2 nanowire arrays based on flexible carbon textiles (RuO2-TiO2 NAs/CT) is synthesized by combining hydrothermal strategy with photodeposition technique. The flexible cathode can be directly used in Li-CO2 battery and exhibit excellent electrochemical performances with lower over-potential for charge/discharge process, higher discharge capacity, and especially, longer cycle life up to 1904 h (238 cycles). Additionally, a flexible battery is also assembled based on the obtained flexible cathode. Meanwhile, we revealed that the polarization of Li-CO2 battery can be regulated with the assistance of illumination.