The commercial NMC811 cathode can provide high specific capacity and energy density but it has poor capacity retention leading short cycle life and severe safety hazards because their instability of layer structure. Whist, spinel LMO cathode has high stability with great capacity retention but low specific capacity and energy density. In this work, blended NMC811/LMO cathode in the ratio of 2:1 can increase the capacity around 69% when compared with pristine LMO. Moreover, the blended NMC811/LMO in the ration of 2:1 can provide the high-capacity retention more than 80% in 450 cycles that higher than pristine NMC811 around 40% and give the highest energy density equal to 189.3 Whkg^-1. Thus, the blended NMC811/LMO can solve intrinsic drawbacks of these two cathode materials (NMC811 and LMO) and can be used to further develop the 18650 batteries in the industrial level to be more efficient.