Cobalt Single Atom-Catalyzed Formation of LiOH in Li-O_(2)Batteries via the Direct 4-Electron Oxygen Reduction Pathway

The formation of LiOH as the discharge product instead of Li_(2)O_(2)in Li-O_(2)batteries(LOBs)is highly desirable due to the associated drawbacks of Li_(2)O_(2)-based chemistry,which involves the generation of reactive oxygen intermediates responsible for substantial side reactions.However,the current challenge lies in the formation pathway of LiOH,which typically requires the chemical hydrolysis of the hazardous LiO_(2)or Li_(2)O_(2)intermediate,posing risks to the battery components.Herein,we report a direct 4e–electrochemical approach to LiOH enabled by a single atom catalyst(SAC)consisting of CoN_(3)moieties embedded in graphene(CoN_(3)-G),while Li_(2)O_(2)is formed on the metal-free nitrogen-doped graphene(NG).The direct 4e–LiOH pathway significantly reduces the parasitic reactions,resulting in negligible damage to the electrolyte and cathode.This stands in strong contrast to the conventional 2e–Li_(2)O_(2)pathway mediated by NG and the indirect LiOH pathway by MnO_(2).Theoretical calculations further clarify that the presence of CoN_(3)sites enhances the adsorption of oxygen-containing intermediates like*OLiO and*Li_(2)O_(2),promoting the protonation of*Li_(2)O_(2)and the cleavage of the O–O bond to form LiOH.This work demonstrates a promising strategy to modulate the reaction pathways in LOBs and broadens the applications of SACs.