One-pot pyro-synthesis of a high energy density LiFePO4-Li3V2(PO4)3 nanocomposite cathode for lithium-ion battery applications

A highly crystalline carbon-coated 0.66LiFePO4
- 0.33Li3V2(PO4)3 (LFP-LVP) nanocomposite was synthesized by a one-pot pyro-synthetic strategy using a polyol medium at low temperature. Prior to any additional heat treatment, electron microscopy confirmed the as-synthesized composite to consist of spherical particles with average diameters in the range of 30-60 nm. A crystal growth phenomenon and particle aggregation was observed upon heat treatment at 800 °C, thus resulting in an increase in the average particle size to 200-300 nm. When tested for a lithium-ion cell, the nanocomposite electrode demonstrated impressive electrochemical properties with higher operating potentials hence enhanced energy densities. Specifically, the composite cathode delivered a high reversible capacity of 156 mAh g−1 at 0.1 C and exhibited a remarkable reversible capacity of 119 mAh g−1, corresponding to an energy density of 46.88 Wh Kg−1 at 6.4 C. When cycling was performed at 6.4 C, the electrode could recover up to 85% of the capacity observed at low current density of 0.1 C, which indicates the excellent rate capability of the nanocomposite electrode. The enhanced performance was attributed to the inclusion of the high potential LVP phase constituent in the present cathode by a simple one-pot polyol-assisted pyro strategy.