Optimization of Microwave Synthesized Carbon Coated Nano LiFePO4 Active Cathode Material Composition for Li-Ion Batteries

Lithium iron phosphate (LiFePO4) is an attractive cathode material for lithium-ion batteries. Among various issues, the most important concern is its low intrinsic electronic conductivity and slow lithium-ion diffusion across the LiFePO4/FePO4 phase boundary during charge/discharge processes which limit the rate performance of this material. Different strategies are being employed to improve its electrochemical performance. The physical technique such as ball-milling of LiFePO4 with carbon black followed by a unique synthesis route like microwave synthesis was used for formation of LiFePO4 which yielded smaller particle size and more uniform size distribution. This carbon coated nano material is electrochemically characterized by fabricating half cells using CR2032 hardware. The preparation of cathodes is required to be optimized to get good electrochemical properties. The ratio of cathode active material, conductive additive acetylene black and binder PVdF to form slurry was optimized by fabricating several coin cells and testing them rigorously. Specific capacities and cycle life obtained for various compositions are reported. For optimized composition, different C-rate discharge characteristics are reported.