Light/Electricity Energy Conversion and Storage for a Hierarchical Porous In S @CNT/SS Cathode towards a Flexible Li-CO Battery.

A photoinduced flexible Li-CO battery with well-designed, hierarchical porous, and free-standing In S @CNT/SS (ICS) as a bifunctional photoelectrode to accelerate both the CO reduction and evolution reactions (CDRR and CDER) is presented. The photoinduced Li-CO battery achieved a record-high discharge voltage of 3.14 V, surpassing the thermodynamic limit of 2.80 V, and an ultra-low charge voltage of 3.20 V, achieving a round trip efficiency of 98.1 %, which is the highest value ever reported (<80 %) so far. These excellent properties can be ascribed to the hierarchical porous and free-standing structure of ICS, as well as the key role of photogenerated electrons and holes during discharging and charging processes. A mechanism is proposed for pre-activating CO by reducing In to In under light illumination. The mechanism of the bifunctional light-assisted process provides insight into photoinduced Li-CO batteries and contributes to resolving the major setbacks of the system.