Lithium ion batteries with Li-rich cathodes is attracting tremendous attention due to its high specific capacity but it also suffers from the undesirable cyclic performance due to the oxygen release and irreversible lithium loss in initial cycle. To offset the tough question of initial lithium loss caused by the formation of SEI, lithium oxide was applied as the extra lithium sources and stabilize agent of Li1.15Ni0.17Co0.11Mn0.57O2, and it is found that a proper amount of lithium oxide can improve the initial charge and discharge capacity. Compared with raw materials, the initial charge and discharge capacity of lithium-rich materials with 6wt% lithium oxide increased by 5% and 6.4%, respectively. The composited cathodes show improved rate capacity and cyclic stability. It was found that the addition of a small amount of lithium oxide did not change the charge and discharge reaction process rather made the oxidation peaks move slightly to the direction of low potential. It was also conducive to the realization of higher capacity and improved the migration of lithium ions gradually after cycling. The reduction of impedance after adding Li2O in Li1.15Ni0.17Co0.11Mn0.57O2 may be the main reason for the improvement of electrochemical performance. (C) 2019 The Electrochemical Society.