Illumination-enhanced oxygen reduction kinetics in hybrid lithium-oxygen battery with p-type semiconductor

Lithium-oxygen battery has attracted extensive attention for its high energy density. However, the lithium peroxide will accumulate at cathode during the discharge process, resulting in large charge-discharge over potential. At present, the photo-assisted system reported in some work is an effective way to reduce charge overpotential. But the effect of photo-assisted process on the discharge potential is rarely studied. In this work, p type semiconductor (lanthanum ferrite) was prepared and the photocurrent reaches 179.4 mu A cm(-2) at 0.7 V (vs RHE) in 0.1 M KOH. It was assembled in the lithium-oxygen battery which was self-designed based on aqueous electrolyte, and the discharge potential of this battery can be improved under illumination due to the enhancement of the oxygen reduction reaction. With light illumination, the LaFeO3 photocathode can promote discharge potential to 3.24 V compare with 2.81 V in dark and stably cycle for more than 400 h.

Automated summary

The lithium-oxygen battery has high energy density but often suffers from charge-discharge overpotential due to the accumulation of lithium peroxide at the cathode. A photo-assisted system has been shown to effectively reduce charge overpotential, but its effect on discharge potential is rarely studied. In this study, a p type semiconductor (lanthanum ferrite) was prepared and assembled in a self-designed lithium-oxygen battery. The battery showed improved discharge potential under illumination, thanks to the enhanced oxygen reduction reaction. The LaFeO3 photocathode promoted the discharge potential to 3.24 V compared to 2.81 V in the dark, and exhibited stable cycling for over 400 hours.