A highly reversible force-assisted Li - CO₂ battery based on piezoelectric effect of Bi_0.5Na_0.5TiO₃ nanorods

The use of light-assisted cathode is regarded as an effective approach to reduce the overpotential of lithium carbon dioxide (Li - CO₂) batteries. However, the inefficient electron-hole separation and the complex discharge-charge reactions hamper the efficiency of CO₂ photocatalytic reaction in battery. Herein, a highly reversible force-assisted Li - CO₂ battery has been established for the first time by employing a Bi_0.5Na_0.5TiO₃ nanorods piezoelectric cathode. The high-energy electron and holes generated by the piezoelectric cathode with ultrasonic force can effectively enhance the carbon dioxide reduction reaction (CDRR) and carbon dioxide evolution reaction (CDER) kinetics, thereby reducing the overpotentials during the discharge-charge processes. Moreover, the morphology of the discharge product (Li₂CO₃) can be modified via the dense surface electrons of the piezoelectric cathode, resulting in the promoted decomposition kinetics of Li₂CO₃ in charging progress. Thus, the force-assisted Li - CO₂ battery with the unique piezoelectric cathode can adjust the output and input energy by ultrasonic wave, and provides an ultra-low charging platform of 3.52 V, and exhibits excellent cycle stability (a charging platform of 3.42 V after 100 h cycles). The investigation of the force-assisted process described herein provides significant insights to solve overpotential in the Li - CO₂ batteries system.