Performance Evaluation of Lithium Vanadium Fluorophosphate in Lithium Metal and Lithium-Ion Cells

Abstract

In this study it is demonstrated that the lithium vanadium fluorophosphate, LiVPO 4 F phase, offers considerable promise as a viable cathode material for commercial lithium-ion batteries. The active material was synthesized using a reaction scheme based on carbothermal reduction. The LiVPO 4 F is isostructural with the known mineral ambygonite, LiAlPO 4 F, crystallizing with a triclinic structure ͑space group, Py͒. Performance evaluation of graphite//LiVPO 4 F lithium-ion cells indicates a reversible material utilization for the LiVPO 4 F of around 130 mAh/g and an average discharge voltage of 4.06 V. Long-term cycling ͑C/5 rate at 23°C͒ of this lithium-ion configuration predicts a cycle life Ͼ500 cycles to around 90% of the original discharge capacity.

Electrochemical performance of LiVPO4F/C composite cathode prepared through amorphous vanadium phosphorus oxide intermediate

“…Compared with LVPF650 and LVPF750, there is no apparent diffraction peaks of Li 3 V 2 (PO 4 ) 3 impurity in XRD patterns of LVPF700, suggesting that LVPF700 comprises only LiVPO 4 F crystal phase and carbon and this composite may have better electrochemical performance. It is noted that the final products prepared by amorphous VPO intermediates synthesized at 650 and 750°C comprise a certain amount of Li 3 V 2 (PO 4 ) 3 impurity while Li 3 V 2 (PO 4 ) 3 is absent in the product synthesized by [22]. The cell parameters for three composites based on a triclinic structure are listed in Table 1, and the results are similar to the previous report [3].…”

Fluoride based electrode materials for advanced energy storage devices

“…The initial attempts at the LiVPO 4 F synthesis resulted in a reversible capacity close to 120 mAh/g. However, after optimization of the fabrication process, improved reversibility and room temperature cycling stability were attained with a discharge capacity close to the 155 mAh/g theoretical capacity at a C/15 rate between 3 and 4.5 V [78,79]. The material was also evaluated in a Li-ion cell configuration utilizing a graphite anode.…”

“…The material was also evaluated in a Li-ion cell configuration utilizing a graphite anode. LiVPO 4 F delivered a 123 mAh/g reversible capacity at an average discharge voltage of 4.06 V, while maintaining good capacity retention over 300 cycles between 3 and 4.4 V at a 1C rate [78,79]. Based on these results, LiVPO 4 F offers a 0.3 V greater discharge voltage and a flatter voltage profile compared to the state of the art LiCoO 2 system, showing the potential of this lithium phosphate system as positive electrode material for Li-ion cells.…”

Investigations on the synthesis and electrochemical performance of Li3V2(PO4)3/C by different methods

“…The mass ratio of active material, acetylene black, and PVDF in the electrodes was 80:10:10 except for special statement. The resulting slurry was pasted on an aluminum foil current 10 20 30 40 50 60 …”

“…Some other transition phosphate polyanion insertion hosts such as LiMnPO 4 [2], LiFePO 4 [3][4][5][6], LiVPO 4 F [7][8][9][10][11][12], and Li 3 V 2 (PO 4 ) 3 [9,[13][14][15][16] have received some recent attention because of their stable framework, relatively high voltage, good lithium ion transport, and large theoretical capacity. With relatively high capacity and suitable operating voltage for the present commercial electrolyte system, Li 3 V 2 (PO 4 ) 3 is considered to be one of the most promising cathode materials among the aforementioned phosphate polyanion hosts.…”