Electrochemical Behaviour of Surface Modified SiO_2-Coated LiNiO_2 Cathode Materials for Rechargeable Lithium-Ion Batteries

摘要

Pristine and SiO_2-coated on layered LiNiO_2 nanoparticles were synthesized by polymeric sol gel process using metal nitrate precursors at 600℃ for 10 h. Effect of SiO_2 coating on the structure and electrochemical properties of the LiNiO_2 cathode material was investigated by using XRD, SEM, Cyclic voltammetry and Charge-discharge techniques. X-ray powder diffraction analysis of SiO_2-coated LiNiO_2 revealed that the coating did not affect the crystal structure and the R-3m space group of the cathode materials compared to uncoated LiNiO_2. Surface morphology of LiNiO_2 and silica coated LiNiO_2 powder materials were characterized by using SEM studies. The galvanostatic charge/discharge studies of the pristine and silica coated LiNiO_2 positive materials were found at 0.5-C rate in the potential range between 3-4.5 V, Silica coated positive electrode materials have improved charge/discharge capacities. Cyclic voltammetry studies have revealed that, short range deintercalation/intercalation process of Li~+ ions and the 2 wt.% relatively narrower peaks with less peak separation. 2 wt.% of SiO_2-coated LiNiO_2 positive material met the structural stability, high reversible capacity and high electrochemical performances.