Synthesis and Electrochemical Performances of Li3V2(PO4)3/C Based Materials in Non-aqueous Electrolyte

Abstract

Li3V2(PO4)3/C (LVP/C) and Fe-doped LVP/C composite materials were synthesized by sol-gel and solid state methods, with different carbon sources. Electrochemical performances were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge. Cyclic voltammetry measured between 3.0 V and 4.3 V vs. Li/Li+ shows that all samples have monoclinic structure, and that during cycling 2 out of 3 lithium ions are deintercalated/intercalated. Electrochemical impedance spectroscopy results show that doped samples have higher charge transfer resistance (Rct), and that samples synthesized by solid state route with glucose as carbon source have the lowest Rct. Galvanostatic measurements between 2.5 V and 4.3 V vs. Li/Li+ show that doped materials have better cyclic stability. Materials synthesized by solid state route have the highest initial capacity of 126 mAh/g for pristine LVP/C and 120.9 mAh/g for Fe-doped LVP/C.