Effect of Different Solvents on the Synthesis of d-Vanadyl Phosphate and Its Performance as Cathode for Li-ion Battery

In the present work d-vanadyl phosphate (VOPO4) was synthesized in the presence of different solvents like water,
ethanol, diethyl ketone and 2-propanol. Role of these solvents on the Li-intercalation behaviour of synthesized
d-VOPO4 has been studied. The solvents affected significantly the size of the crystallites and the level of impurities
in the synthesized material. d-VOPO4 synthesized using water as solvent, possessed a significant Li-intercalation
capacity ca., 124 mAh.g–1 at 3.7 V corresponding to 75% of its theoretical capacity. Among the organic solvents
used, sample prepared using ethanol exhibited the highest Li intercalation capacity. Small amount of b-phase was
observed in the synthesized d-VOPO4 (with phosphate/vanadium ratio of 2) using ethanol and Li-intercalation
capacity of this phase was about 137 mAh.g–1, corresponding to 85% of the theoretical capacity. The capacity was
found to be almost stable at 110 mAh.g–1 over 100 cycles.