Surface acidity regulation for boosting Li2O2 decomposition towards lower charge overpotential Li-O2 batteries

The discharge product Li2O2 with a wide band gap requires a high potential to decompose, hindering the practical application of Li-O2 batteries (LOBs). Herein, a surface acidity regulation strategy is proposed to boost Li2O2 decomposition through doping Mn atoms into Co3O4 catalyst. Experimental results and theoretical calculations demonstrate that the doped Mn atoms increase empty orbitals near the Fermi level to enhance the surface acidity of Co3O4. Among the doped catalysts, the 15%Mn-doped Co3O4 with a suitable surface acidity of 347.5 mu mol g- 1 promotes the electronic transfer from Li2O2 to Co3O4 and coordinates the reduction of the desorption barriers of Li+ and O2, which effectively boosts the decomposition of Li2O2 to reduce the charge overpotential of LOBs, thus achieving a low charge overpotential (1.18 V at 1000 mA g- 1) and great cyclic stability (350 cycles at 4000 mA g- 1) in LOBs. Even under the limited specific capacity of 2000 mAh g- 1, the 15%Mn-doped Co3O4-based LOBs exhibit a great cycle stability of 250 cycles. This work elucidates the critical role of catalyst surface acidity regulation in boosting Li2O2 decomposition, thus reducing the charge overpotential of LOBs.