A photo-assisted electrocatalyst coupled with superoxide suppression for high performance Li-O2 batteries

Li-O 2 batteries are one of the most promising next generation batteries due to their high energy density . However, they suffer from high charge overpotentials and severe side reactions. Here we report a bifunctional CeVO 4 catalyst that not only lowers the charge potential by a photo-assisted mechanism, more importantly, promotes the efficient conversion of highly reactive oxidative intermediates to Li 2 O 2 , thus avoiding the oxidative decomposition of the electrolyte/cathode during discharge. Benefiting from its efficient electrocatalysis and the improved charging ability, 1.6x higher discharge capacity up to 6.14 mAh cm -2 , low charge potential of 3.48 V and stable cycling performance are simultaneously achieved. Theoretical calculation and in-situ Raman spectra confirm the superior adsorptive and conversion ability of superoxide species by electrochemical reduction and chemical disproportionation reactions on the CeVO 4 catalyst. These results indicate an effective strategy to break through the reported limitations of photo-assisted cathodes that are of a low electrocatalysis ability and limited discharge capacity. The significance of retaining a high energy density in photo-assisted Li-O 2 batteries is highlighted.