Fluid-Induced Piezoelectric Field Enhancing Photo-Assisted Zn-Air Batteries Based on a Fe@P(V-T) Microhelical Cathode.

Abstract

Photo-assisted Zn-air batteries can accelerate the kinetics of oxygen reduction and oxygen evolution reactions (ORR/OER); however, challenges such as rapid charge carrier recombination and continuous electrolyte evaporation remain. Herein, for the first time, piezoelectric catalysis is introduced in a photo-assisted Zn-air battery to improve carrier separation capability and accelerate the ORR/OER kinetics of the photoelectric cathode. The designed microhelical catalyst exploits simple harmonic vibrations to regenerate the built-in electric field continuously. Specifically, in the presence of the low-frequency kinetic energy that occurs during water flow, the piezoelectric-photocoupling catalyst of poly(vinylidene fluoride-co-trifluoroethylene)@ferric oxide(Fe@P(V-T)) is periodically deformed, generating a constant reconfiguration of the built-in electric field that separates photogenerated electrons and holes continuously. Further, on exposure to microvibrations, the gap between the charge and discharge potentials of the Fe@P(V-T)-based photo-assisted Zn-air battery is reduced by 1.7 times compared to that without piezoelectric assistance, indicating that piezoelectric catalysis is highly effective for enhancing photocatalytic efficiency. This study provides a thorough understanding of coupling piezoelectric polarization and photo-assisted strategy in the field of energy storage and opens a fresh perspective for the investigation of multi-field coupling-assisted Zn-air batteries.