Superior charge-transfer kinetics of NASICON-type Li3V2(PO4)3 cathodes by multivalent Al3+ and Cl− substitutions

• DOI: 10.1016/j.electacta.2013.02.118
• Publication Date: 2013-03-01T18:57:45Z
• Authors: J.N. Son; S.H. Kim; M.C. Kim; G.J. Kim; V. Aravindan; Y.G. Lee; Y.S. Lee
• Keywords: 02 engineering and technology; 0210 nano-technology; 7. Clean energy

Abstract The kinetic properties of Li insertion in NASICON-type Li 3 V 2 (PO 4 ) 3 cathodes were enhanced substantially by Al 3+ and Cl − multivalent substitutions of various concentrations. Pristine and carbon coated, Al-doped Li 3 V 2 (PO 4 ) 3 were also prepared by a conventional solid-state approach under optimized conditions. Samples phase purity was investigated through X-ray diffractometry. Li insertion was studied in half-cells at 3-4.8 V vs. Li for the removal of 3 mol of Li. Carbon-coated Li 3 V 1.98 Al 0.02 (PO 4 ) 2.99 Cl 0.01 showed the highest reversible insertion of 2.71 mol of Li (178 mAh g −1 ) at a current density of 0.2 mA cm −2 . It showed a capacity retention of over 80% after 100 cycles. Cl − substitution led to improved performance under harsh conditions of 15 C rate and high temperature (50 °C). The enhancement of Li ion kinetics was demonstrated through cyclic voltammetry in a two-electrode configuration and electrochemical impedance spectroscopy confirmed the enhanced conductivity.