Enhanced cycling stability of LiNi0.8Co0.1Mn0.1O2 by reducing surface oxygen defects

Abstract

The cycling performance of LiNi0.8Co0.1Mn0.1O2 cathode material has been enhanced by improvement nickel-rich material on surface oxygen-keeping capability. LiNi0.8Co0.1Mn0.1O2 cathode material with lower surface oxygen defects is synthesized via covering Ni0.8Co0.1Mn0.1(OH)2 with manganese acetate and sintering with LiOH·H2O at high temperature. A good layered structure with lower surface oxygen defects in the outer layer has been identified by XRD, FFT, HADDF-STEM and XPS. Compared with the bare material maintaining 77.2% capacity retention, the modified LiNi0.8Co0.1Mn0.1O2 materials Exhibit 90.4% capacity retention and 166 mAh·g−1 after 200 cycles at 1C rate. Electrochemical impedance spectroscopy, XRD and SEM of cycled electrodes tests results provide evidence that the improved cycling performance is mainly attributed to stable surface oxygen, the suppression of the interface reaction between the cathode and electrolyte and the improvement in the structural stability of material.