Boron-doped Ketjenblack is attempted as cathode catalyst for non-aqueous rechargeable Li–O_2 batteries. The boron-doped Ketjenblack delivers an extremely high discharge capacity of 7193 m Ah/g at a current density of 0.1 m A/cm2, and the capacity is about 2.3 times as that of the pristine KB. When the batteries are cycled with different restricted capacity, the boron-doped Ketjenblack based cathodes exhibits higher discharge platform and longer cycle life than Ketjenblack based cathodes. Additionally, the boron-doped Ketjenblack also shows a superior electrocatalytic activity for oxygen reduction in 0.1 mol/L KOH aqueous solution. The improvement in catalytic activity results from the defects and activation sites introduced by boron doping. Boron-doped Ketjenblack was attempted as a cathode catalyst for non-aqueous rechargeable Li-O 2 batteries. The boron-doped Ketjenblack delivers an extremely high discharge capacity of 7193 m Ah / g at a current density of 0.1 m A / cm 2, and the capacity is about 2.3 times as that of the pristine KB. When the batteries are cycled with different restricted capacity, the boron-doped Ketjenblack based cathodes exhibits higher discharge platform and longer cycle life than Ketjenblack based cathodes. Additionally, the boron-doped Ketjenblack also shows a superior electrocatalytic activity for oxygen reduction in 0.1 mol / L KOH aqueous solution. The improvement in catalytic activity results from the defects and activation sites introduced by boron doping.