Search

We have synthesized LiMn2–xFexO4 (x = 0, 0.25, and 0.50) cathode materials for applications in Li ion rechargeable batteries via sol-gel method. We studied thermal characteristics of as synthesized materials using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). In order to optimize the synthesis conditions, we studied X-ray diffraction (XRD) of synthesized cathode materials at various temperatures, based on the transitions obtained from DSC/TGA. The XRD results can be co-related to the thermal behavior of the synthesized cathode materials and the synthesis conditions optimized.

High energy density batteries are essential for portable electronic devices e.g. Laptops, mobile phones, iPads, toy etc. Besides this, high energy density batteries are also required for power tools and hybrid electric vehicles. Commercially available lead-acid batteries are toxic and have low energy density and not suitable for electronic devices. Advanced Li-ion batteries possess high specific energy as compared to existing rechargeable battery technologies. Commercially available Li ion rechargeable batteries having LiCoO2 as cathode materials are toxic and expensive due to the presence of cobalt. Additional disadvantage of LiCoO2 based batteries is their low operating voltage (3 V), which restricts their application for hybrid electric vehicles and power tools. It has already been reported that the charge-discharge characteristics and cycleability of LiMn2O4 can be improved by substituting the Mn3+ ion with transition metals e.g. Cr, Co, Ni, Cu etc. To increase the energy density of the Li ion rechargeable batteries we will be exploring the cathode materials, working in higher operating voltage (~5V) range. We have synthesized LiMn2-xFexO4 cathode materials for Li ion rechargeable batteries. The concentration of Fe varies from 0.1 to 0.5 with an increment of 0.1. The cathode materials were synthesized by sol-gel method and calcined at various temperature in the range of 800 oC to 950 oC. The synthesized materials were physically characterized by X-ray diffraction (XRD), differential thermal scanning calorimetry (DSC), micro-Raman spectroscopy and scanning electron microscopy. We obtained phase pure Fd3m structure in all synthesized compounds. The electrochemical characterization were carried out in a coin cell configuration using cyclic voltammetry, charge-discharge characteristics, impedance spectroscopy and cycleability. Cyclic voltametric studies reveal the reversible electrochemical properties of LiMn2-xFexO4 cathode materials. The detailed results and discussion on physical and electrochemical properties of LiMn2-xFexO4 cathode materials will be presented in the ECS 229th meeting.