Correlation between the structural, electrical and electrochemical performance of layered Li(Ni0.33Co0.33Mn0.33)O-2 for lithium ion battery

Abstract

The Li(Ni0.33Co0.33Mn0.33)O2 (LNCMO) cathode material is prepared by poly(vinyl pyrrolidone) (PVP)-assisted sol-gel/hydrothermal and poly(ethylene glycol)-block-poly(propylene glycol)-block-poly (ethylene glycol) (Pluronic-P123)-assisted hydrothermal methods. The compound prepared by PVP-assisted hydrothermal method shows a comparatively higher electrical conductivity of ~2 × 10−5 S cm−1 and exhibits a discharge capacity of 152 mAh g−1 in the voltage range of 2.5 to 4.4 V, for a C-rate of 0.2 C, whereas the compounds prepared by P123-assisted hydrothermal method and PVP-assisted sol-gel method show a total electrical conductivity in the order of 10−6 S cm−1 and result in poor electrochemical performance. The structural and electrical properties of LNCMO (active material) and its electrochemical performance are correlated. The difference in percentage of ionic and electronic conductivity contribution to the total electrical conductivity is compared by transference number studies. The cation disorder is found to be the limiting factor for the lithium ion diffusion as determined from ionic conductivity values. © 2015, Springer-Verlag Berlin Heidelberg.