Beneficial effect of incorporating Ni-rich oxide and layered over-lithiated oxide into high-energy-density cathode materials for lithium-ion batteries

Layer structured Ni-rich oxides with high energy density suffer from an aggressive side reaction at the deep-charged state, resulting in consequent structure collapse and capacity fading. Herein, a facile modification strategy has been developed by designing electrochemically stable lithium-rich layered oxides as the shell and high-energy-density Ni-rich oxides as the core. Mn²⁺, Co²⁺, and Ni²⁺ solutions are introduced to form Mn_0.54Ni_0.13Co_0.13(OH)_1.6, which is homogeneously coated on LiNi_0.80Co_0.15Al_0.05O₂ composite. Materials incorporating advantages of Ni-rich oxides and layered over-lithiated oxides are obtained after simple heat treatment. Li_1.20Mn_0.54Ni_0.13Co_0.13O₂ coating improves the cycling performance of LiNi_0.80Co_0.15Al_0.05O₂ pronouncedly even at a high cut-off voltage. 1% layered over-lithiated oxide modified materials show discharge capacities of 196.6, 188.8, and 182.9 mAh g^-1 at the rates 0.2, 0.5, and 1 C, respectively, in square full-cells between 2.8 and 4.35 V, and display an improved cycling performance with 82.6% capacity retention during 1000 cycles at 1 C rate.