Effect of sintering time on the synthesize of the multi-layered core-shell LiVOPO4-Li3V2(PO4)(3) composite for Li-ion batteries

作者：Shen Chao; Zhang Bao; Zheng Jun chao; Han Ya dong; Zhang Jia feng^*

来源：Journal of Alloys and Compounds, 2015, 622: 771-776.

DOI：10.1016/j.jallcom.2014.10.198

• Lithium ion battery
• Cathode material
• LiVOPO4-Li3V2(PO4)(3)
• Electrochemical properties

A novel multi-layered core-shell LiVOPO4-Li3V2(PO4)(3) composite is synthesized and used as the cathode of lithium ion battery in this work. Composites with different compositions can be obtained by calcining Li3V2(PO4)(3) at 350 degrees C for different time in air atmosphere. XRD, SEM, TEM and electrochemical methods are employed to investigate the effect of sintering time on the structure and properties of the prepared LiVOPO4-Li3V2(PO4)(3) cathodes. Results indicate that the obtained composites were comprised of a triclinic LiVOPO4 (LVOP) as well as a monoclinic Li3V2(PO4)(3) (LVP), and the weight ratio of LVOP increases as prolonging the sintering time based on the Rietveld refinement results. A complete particle in the composite sintered with 2 h in air was composed of a core LVP, a shell LVOP as well as some amorphous carbon observed by TEM images, and results from XPS also indicate that the valence of element V was changed from +4 (the shell) to +3 (the core) in the particles. The LiVOPO4-Li3V2(PO4)(3) composite synthesized at 2 h in air shows the best electrochemical performance with a discharge capacity of 132.8 mAh g(-1) at 45 mA g(-1), and the capacity was 126.8 mAh g(-1) after 100 cycles.

• 单位
  中南大学