PHYSICO-CHEMICAL CHARACTERIZATION OF LITHIUM-RICH METAL OXIDES : Li1+xM1-xO2 [M=Mn, Ni, Fe and x=0.2] CATHODE MATERIAL FOR LITHIUM-ION BATTERIES

Abstract

A cathode material is key factor influencing the high power and high efficiency performances of lithium-ion batteries. The present work attributes to finding a alternative cathode material which would have high cell voltage, high life cycle, high specific energy, safety and cost effective. So a new cathode material of layered structure, were successfully synthesized by sol-gel route. The AC conductivity performance in lithium-ion batteries was also measured by LCR Meter. The alternative cathode materials as ordinate of well establish layered cathode material, LiCoO2 are enormously in demand for lithium ion batteries due to the costly of Co based cathode at high temperature (>900C), toxicity and high cost. LiMnO2, with its higher theoretical capacity (280 mAhg-1), lower price and environmental friendliness seems to be an attractive alternative cathode material for Lithium-ion Batteries. This material, however, is structurally unstable, which implies insufficient cyclability of Manganese oxide based batteries. There have been numerous attempts to improve its structural stability. Addition of extra lithium will tend to push the manganese away from trivalent to tetravalent, thus minimizing the impact of any Jahn-Teller distortion coming from Mn3+. In the present investigation, synthesis of alternative Lithium-Rich Metal oxides Li1+xM1-xO2 [M=Mn, Ni, Fe and x=0.2] cathode material in air & inert atmosphere has been carried out by solgel route of chemical synthesis using citric acid as chelating agent. It is found that by manganese substitution with nickel and iron improve the structural stability. Hence, nickel and Iron doped Li1+xMn1-xO2 (x=0.2) having general formula Li1+x{Mn0.4Ni0.4Fe0.2}1- xO2 (x=0.2) has the potential to fulfil the above criteria to become a better ordinate of alternative cathode material. The ccomposite exhibit the excellent electrical performance with enhanced AC conductivity. The improved performance was attributed to its well ordered layered structure and small particles with uniform size distribution. The proposal layered materials containing iron may a low cost and eco-friendly energy source materials for large scale Lithium-Ion batteries application However, the electrochemical performance of the above synthesized cathode material yet to be performed to see the real capacity of cathode material. The proper phase confirmation of Li1+xM1-xO2 (x=0.2) and substituted with Ni and Fe has been confirmed by XRD and uniformly distributed prismatic shape of particle size is observed by SEM.