Improving the electrochemical performance of lithium vanadium fluorophosphate cathode material: Focus on interfacial stability.

To improve the stability of LiVPO 4 F electrode/electrolyte interface, Li 3 PO 4 is used to modify LiVPO 4 F composite (P-LVPF) for the first time. Morphological characterization shows that LiVPO 4 F particles are wrapped by amorphous carbon and lithium ionic conductor Li 3 PO 4 as the interlayer and outer layer, respectively. Compared to the pristine sample, the resultant P-LVPF exhibits greatly improved rate capability and elevated-temperature cycle performance when applied as the cathode material for lithium ion batteries. Specifically, the Li 3 PO 4 modified sample specific capacity maintains 77.6% at 1 C after 100 cycles under 55 °C. Such improvement is attributed to the fact that the Li 3 PO 4 coating layer not only acts as a good ionic conductor for LiVPO 4 F, but also serves as a physical barrier between electrode and electrolyte which can build a stable interface. [ABSTRACT FROM AUTHOR]