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

• Published in: Journal of power sources 2016-10, Vol.329, p.553-557
• Main Authors: Wang, Jiexi, Liu, Zhaomeng, Yan, Guochun, Li, Hangkong, Peng, Wenjie, Li, Xinhai, Song, Liubin, Shih, Kaimin
• Format: Article
• Language: English
• Subjects: Cathode material; Interfacial stability; Lithium ion battery; Lithium phosphate coating; Lithium vanadium fluorophosphates
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2016.08.131

To improve the stability of LiVPO4F electrode/electrolyte interface, Li3PO4 is used to modify LiVPO4F composite (P-LVPF) for the first time. Morphological characterization shows that LiVPO4F particles are wrapped by amorphous carbon and lithium ionic conductor Li3PO4 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 Li3PO4 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 Li3PO4 coating layer not only acts as a good ionic conductor for LiVPO4F, but also serves as a physical barrier between electrode and electrolyte which can build a stable interface. [Display omitted] •Li3PO4 coating builds stable LiVPO4F/electrolyte interface for the first time.•LiVPO4F coated with Li3PO4 shows enhanced cycle performance at 55 °C.•Li3PO4 is proposed to act as a physical barrier as well as a Li+ transfer media.