Improved electrochemical properties of chromium substituted in LiCr1-xNixO2 cathode materials for rechargeable lithium-ion batteries

Pristine- and chromium-substituted LiNiO2 nanoparticles were synthesized by sol-gel method using nitrate precursor at 800 A degrees C for 12 h. Physical properties of the synthesized product were analyzed using Fourier transform infrared, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive analysis X-ray. XRD studies revealed a well-defined layer structure and a linear variation of lattice parameters with the addition of chromium and no impurities. Surface morphology and particle size of synthesized materials were changed with chromium addition using SEM and TEM analyses. Assembled lithium-ion cells were evaluated for charge/discharge studies at different rates, cyclic voltammetry, and electrochemical impedance spectra. The initial discharge capacity of LiNiO2 cathode material was found to be 168 mA hg(-1); however, discharge capacity increased in chromium substitution. Electrochemical impedance spectroscopy revealed that LiCr0.10Ni0.90O2 could enhance charge transfer resistance upon cycling. The substitution of Ni with chromium, LiCr0.10Ni0.90O2, had better cycle life, low irreversible capacity, and excellent electrochemical performance.