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

The discharge product Li 2 O 2 with a wide band gap requires a high potential to decompose, hindering the practical application of Li–O 2 batteries (LOBs). Herein, a surface acidity regulation strategy is proposed to boost Li 2 O 2 decomposition through doping Mn atoms into Co 3 O 4 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 Co 3 O 4 . Among the doped catalysts, the 15%Mn-doped Co 3 O 4 with a suitable surface acidity of 347.5 μmol g −1 promotes the electronic transfer from Li 2 O 2 to Co 3 O 4 and coordinates the reduction of the desorption barriers of Li + and O 2 , which effectively boosts the decomposition of Li 2 O 2 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 Co 3 O 4 -based LOBs exhibit a great cycle stability of 250 cycles. This work elucidates the critical role of catalyst surface acidity regulation in boosting Li 2 O 2 decomposition, thus reducing the charge overpotential of LOBs.