Synthesis and Characterization of Gradient Cathode Material for Lithium-ion Batteries

Gradient cathode material of LiNi0.7Co0.15Mn0.15O2 was synthesized by mixing hydroxide co-precipitated precursors with 8% excess LiOH center dot H2O. Structure and electrochemical properties of the material was characterized by X-ray diffraction (XRD), scanning electronic microscope (SEM), galvanostatic charge-discharge test and electrochemical impedance spectroscopy (EIS). The results indicate that the typical crystal of the material is alpha-NaFeO2. The particles are formed by 200nm similar to 500nm crystals. The gradient material sintered at 800 degrees C shows the best electrochemical performance, the initial discharge capacity of the material is 164.45mAh.g(-1) at 0.2C, its discharge capacity retention of 86% at 2C and with lower electrochemical impedance.