Optimizing conditions and improved electrochemical performance of layered LiNi1/3Co1/3Mn1/3O2 cathode material for Li-ion batteries

Herein, we have explored performance of layered LiNi1/3Co1/3Mn1/3O2 (NCM111) cathode material for Li ion battery applications, prepared by different preparation strategies namely co-precipitated mixed hydroxide and solid state high temperature approach combined with high-temperature calcination. The effect of crystal structure and morphology of the obtained materials were characterized by means of X-ray diffraction and scanning electron microscopy. X-ray analysis reveals that the observed lattice parameter ratio c/a is greater than 4.89 for materials with different approaches, which indicates the formation of hexagonal layered alpha-NaFeO2 structure. The electrochemical properties of the materials were thoroughly characterized by means of charge-discharge experiments and electrochemical impedance spectroscopy. The direct solid state synthesized NCM111 material exhibits a low retention and discharge capacity of 60 mAh g(-1) at the end of 50 cycles with high irreversible capacity during cycling. The present studies have shown that the importance of material synthesis route and its sintering process, prepared at 900 degrees C for 8 h results low cation mixing between Li and metal ions layer in NCM111 lattice compared to other sintered samples, resulting in superior electrochemical performance. The reversible capacity of 175 mAh g(-1) is noticed at C/10 rate within the voltage window of 2.5-4.4 V for 900 degrees C treated sample. Even at C/3 rate, a stable high reversible capacity of 145 mAh g(-1) is obtained with high capacity retention of 95%. The Rietveld and EIS spectroscopic analysis conforms the existence stable layered structure and electrode, interface for NCM11 approached through co-precipitation.

Automated summary

This study investigated the performance of layered LiNi1/3Co1/3Mn1/3O2 (NCM111) cathode material prepared by different methods, with the 900 degrees C treatment for 8 hours showing superior electrochemical properties. The importance of material synthesis route and sintering process on the cation mixing and electrochemical performance was highlighted.