Lithium cobalt fluorophosphate, Li(2)CoPO(4)F, is successfully synthesized by a solid state reaction under Ar flow at 700 °C. X-ray diffraction and scanning electron microscopic studies are utilized to analyze the structural and morphological features of the synthesized materials, respectively. The presence of fluorine is also supported by energy-dispersive X-ray spectroscopy. The electrochemical properties are evaluated by means of Li/Li(2)CoPO(4)F half-cell configurations in both potentiostatic and galvanostatic modes. The Li/Li(2)CoPO(4)F cell delivers an initial discharge capacity of 132 mA h g(-1) at a current density of 0.1 mA cm(-2) between 2.0 and 5.1 V at room temperature. Due to the higher operating potential of the Co(2+/3+) couple in the fluorophosphate matrix, this cell shows a capacity retention of only 53% after 20 cycles, still the material delivered 108 mA h g(-1) at a high current rate of 1 C. Cyclic voltammetric studies corroborate the insertion and extraction of Li(+) ions by a single phase reaction mechanism during cycling.

We report the synthesis and optimization of metal (Mn, Fe and Al) doped NASICON type Li 3 V 2 (PO 4 ) 3 by solid-state reaction method. Among the metal doping, 0.02 mol concentration of Al is found better performing electrode while approaching the removal of three moles of lithium between 3-4.8 V vs. Li. Adipic acid with various concentrations is used to generate in-situ carbon layer over the 0.02 mol Al doped Li 3 V 2 (PO 4 ) 3 particulates (Li 3 V 1.98 Al 0.02 (PO 4 ) 3 ). Presence of carbon on the surface of particulates is confirmed by TEM and Raman analysis. Half-cell Li/C-Li 3 V 1.98 Al 0.02 (PO 4 ) 3 (0.15 mol of adipic acid) exhibited the highest reversible capacity of ∼182 mAh g −1 (2.77 moles of lithium) at a current density of 0.1 mA cm −2 compared to rest of the adipic acid concentrations. Further, the cell retained 83% of capacity after 50 galvanostatic charge-discharge cycles at ambient conditions. Li-insertion/extraction mechanism and improvement in electronic conductivity profiles are validated through cyclic voltammetry and electrochemical impedance spectroscopy, respectively.