A Force-Assisted Li-O₂ Battery Based on Piezoelectric Catalysis and Band Bending of MoS₂/Pd Cathode

The high overpotential caused by the slow kinetics of oxygen reduction (ORR) and oxygen evolution (OER) has greatly limited the practical application of lithium-oxygen (Li-O-2) batteries. The adoption of force-field-assisted system based on a newly developed piezocatalysis is promising in reducing the overpotential. Herein, a force-assisted Li-O-2 battery is first established by employing MoS2/Pd nanocomposite cathode, in which the piezoelectric polarization as well as built-in electric field are formed in MoS2 piezoelectric catalyst under ultrasound activation, leading to the continuously separated electrons and holes to enhance the ORR and OER kinetics. Moreover, the introduction of Pd can promote the electrons transfer and further inhibit the complexation of electron-hole pairs, contributing to enhanced catalytic activity in the decomposition/generation of discharge products, resulting in reduced discharge/charge overpotentials. Thus, the force-assisted MoS2/Pd-based Li-O-2 battery is capable of adjusting the output and input energies by the assisted ultrasonic wave. An ultra-low charging platform of 2.86 V and a high discharging platform of 2.77 V are achieved. The proposed unique force-assisted strategy can also be applied to lithium carbon dioxide battery system through the effective reduction and separation of CO2 and CO32-, providing significant insights in achieving efficient energy conversion for metal-air batteries.