Nano-Al2O3 Coated Li-rich Cathode Material Li1.2Ni0.13Co0.13Mn0.54O2 for Highly Improved Lithium-ion Batteries

The lithium-rich cathode material Li1.2Ni0.13Co0.13Mn0.54O2 were coated uniformly by nano-Al2O3 for highly stable lithium-ion batteries. The optimum content of nano-Al2O3 coating on the structure, surface morphology and electrochemical properties were systematically studied by X-ray diffraction (XRD) , scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM and TEM results show that the surface of the lithium-rich cathode material is evenly coated with nano-Al2O3. XRD results show that the as-synthesized materials have a layered structure. Electrochemical test results show that the nano-Al2O3 coating is beneficial to improving the discharge specific capacity, rate performance and cycle stability. The nano-Al2O3 coated Li1.2Ni0.13Co0.13Mn0.54O2 material has a specific discharge capacity of 249. 7 mA . h/g with excellent cycling stability(89. 5% capacity retention after 100 cycles). Cyclic voltammetry (CV) and electrochemical impedance(EIS) results show that nano-Al2O3 coating can effectively inhibit the erosion of HF , reduce electrode material/electrolyte interface side-reactions , decrease polarization , reduce interface impedance and charge transfer impedance. This work suggests that the nano-Al2O3 coating is an effective route to significantly improve the electrochemical performance of lithium-rich cathode materials.