Surface modification of nanocrystalline LiCoO2 particles with rare earth oxides using polymeric resin process

B. Nageswara Raoa, M. Venkateswarlub, N. Satyanarayana
PONDICHERRY UNIVERSITY, IN

Keywords: nanocrystalline LiCoO2 particles, surface modification, X-ray diffraction, Fourier transform infrared spectroscopy, SEM, XRF, impedance, conductivity

Summary:

Among the available positive electrode materials, layer structured LiCoO2 is the most preferred one in commercial Li-ion batteries. However, LiCoO2 exhibits a capacity fading at high rates due to its structural instability and reactivity with electrolyte. In order to mitigate this problem, attempts have made through doping of metal ions (Al, Mg, Co, Cu, etc.) and coating of metal oxides (ZrO2, Al2O3, TiO2, SiO2, B2O3, etc.) over LiCoO2 particles. In the present work, nanocrystalline LiCoO2 particles were prepared using ethylene glycol assisted Pechini process and newly developed polymeric resin process was used for uniform coating of rare earth oxides (Sm2O3, La2O3) over LiCoO2 particles. The prepared powders were characterized using TG/DSC, FTIR, XRD, SEM and XRF. The electrical conductivities of the prepared materials were evaluated through impedance measurements.The XRD patterns of coated LiCoO2 do not exhibit any peaks corresponding to Sm2O3 and La2O3 phases, which confirm the amorphous nature of coatings over LiCoO2 particles. FTIR spectral results confirm the formation of Sm2O3 and La2O3 structures over nanocrystalline LiCoO2 particles. Conductivities of bare and Sm2O3, La2O3 coated nanocrystalline LiCoO2 particles are found to be 6.597 X 10-6 ohm-1 cm-1, 4.766 X 10-6 ohm-1 cm-1 and 4.336 X 10-6 ohm-1 cm-1 respectively.