Magnetic and Optical Field Multi-Assisted Li-O2 Batteries with Self-Regulated Charge and Discharge

Abstract

The photo-assisted lithium-oxygen (Li-O2) system emerged as an important direction for future development by effectively reducing the large overpotential in Li-O2 batteries. However, the advancement is greatly hindered by the rapidly recombined photoexcited electrons and holes upon the discharging and charging processes. Herein, we make a breakthrough in overcoming these challenges by developing a new magnetic and optical field multi-assisted Li-O2 battery with 3D porous NiO nanosheets on the Ni foam (NiO/FNi) as a photoelectrode. Under illumination, the photogenerated electrons and holes of the NiO/FNi photoelectrode play a key role in reducing the overpotential during discharging and charging, respectively. By introducing the external magnetic field, the Lorentz force acts oppositely on the photogenerated electrons and holes, suppressing the recombination of charge carriers. The magnetic and optical field multi-assisted Li-O2 battery achieves an ultra-low charge potential of 2.73 V, a high energy efficiency of 96.7%, as well as a good cycling stability of 200 h. This external magnetic and optical field multi-assisted technology paves a new way of developing high-performance Li-O2 batteries and other energy storage systems.