LiVPO4F/Li3V2(PO4)3 nanostructured composite cathode materials prepared via mechanochemical way

• Published in: Journal of solid state electrochemistry 2014, Vol.18 (5), p.1389-1399
• Main Authors: Kosova, Nina V., Devyatkina, Evgeniya T., Slobodyuk, Arseny B., Gutakovskii, Anton K.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Electrochemistry; Energy Storage; Original Paper; Physical Chemistry
• ISSN: 1432-8488; 1433-0768
• DOI: 10.1007/s10008-013-2213-1

Single-phase LiVPO 4 F and LiVPO 4 F/Li 3 V 2 (PO 4 ) 3 nanostructured composite cathode materials were prepared by heating of the VPO 4  + LiF mechanochemically activated mixture to 700 °C and subsequent quick or slow cooling to room temperature, respectively. The formation of the composites was proved by a combination of different physico-chemical methods, including XRD, FTIR, 6 Li and 31 P NMR, SEM, TEM, and HRTEM. It has been shown that in the composites LiVPO 4 F and Li 3 V 2 (PO 4 ) 3 nanocrystals well inset into each other resulting in the nanodomain composite formation. Charge–discharge curves of the composites have a sloping profile both in the high-voltage (3.0–4.5 V) and in the low-voltage (1.3–2.5 V) ranges, noticeably different from plateaus for a phase-pure LiVPO 4 F, thus indicating a probable change of a two-phase regime of lithium intercalation for a single-phase one. Enhanced rate capability of the LiVPO 4 F/Li 3 V 2 (PO 4 ) 3 composites is associated with their microstructure and high ionic conductivity of Li 3 V 2 (PO 4 ) 3 .