SYNTHESIS AND CHARACTERIZATION OF FLUOROPHOSPHATE BASED Li-ION BATTERY CATHODE MATERIAL -LiVPO4F

Abstract

Rechargeable lithium-ion batteries are a powerhouse for modern electronic applications due to high gravimetric and volumetric energy density and long cycle life. The cathode material is the base of all important characteristic in a Li-ion battery. The first generation of cathode materials for Li-ion batteries are mixed oxides either spinal or its derivatives has been commercialized. To improve the intrinsic property of the cathode material, we can utilize all possible oxidation state of a transition metal. Also, the polyanion cathode material can join different units in the anion sub-lattice. Tavorite is a new class of advanced cathode materials for next-generation Li-ion batteries. It has two cation and tow anions in structure. Fluorine is the most ABSTRACT electronegative Lithium vanadium fluorophosphates is a 4V cathode material with the theoretical capacity of 156 mAh/g. LiVPO element of electrochemical series and oxygen and fluorine is similar in size. So, fluorine can easily substitute in the anion sublattice. 4F shows, high voltage, long cycle life, excellent rate capability, high-energy density, and a good thermal and chemical stability. LiVPO4F is the most promising cathode material for next generation Li-ion batteries. The inherent stability of the polyanion group and presence of fluorine-ion in the structure are helpful to increase electrochemical properties. LiVPO4 The synthesis of LiVPOF are receiving more sattentions because of their good thermal and chemical stability. 4F is a difficult task due to the presence of polyanion group and fluorine simultaneously. LiVPO4F successfully synthesized by Sol-gel method. X-ray diffraction studies represent the pure phase of synthesized LiVPO4F. The Rietveld refinement of the sample are done by RIR method (PDXL2) which shows, that the wt.% of a pure phase of LiVPO4F (approximately 96%) is found to be remarkable. Also, the wt.% of Li3V2(PO4)3 is quite low (4.2%). The morphology and crystalline size are studied by SEM and EDX. The thermal analysis (TGA and DTA) and FTIR shows the good thermal stability of the sample. Electrochemical testing of the final product was performed using CV, GCD and EIS technique. Stability of the electrode material was checked up to 25th cycle using CV and GCD and was found to be good.