Carbon coated NASICON type Li3V2-xMx(PO4)3 (M=Mn, Fe and Al) materials with enhanced cyclability for Li-Ion batteries

• Main Authors: Son, J. N., Kim, G. J., Kim, M. C., Kim, S. H., Lee, Y. G., Lee, Y. S., Aravindan, Vanchiappan
• Other Authors: Energy Research Institute @ NTU (ERI@N)
• Format: Article
• Language: English
• Published: 2013
• Online Access: https://hdl.handle.net/10356/106207; http://hdl.handle.net/10220/10181
• Institution: Nanyang Technological University

We report the synthesis and optimization of metal (Mn, Fe and Al) doped NASICON type Li3V2(PO4)3 by solid-state reaction method. Among the metal doping, 0.02 mol concentration of Al is found better performing electrode while approaching the removal of three moles of lithium between 3-4.8 V vs. Li. Adipic acid with various concentrations is used to generate in-situ carbon layer over the 0.02 mol Al doped Li3V2(PO4)3 particulates (Li3V1.98Al0.02(PO4)3). Presence of carbon on the surface of particulates is confirmed by TEM and Raman analysis. Half-cell Li/C-Li3V1.98Al0.02(PO4)3 (0.15 mol of adipic acid) exhibited the highest reversible capacity of ∼182 mAh g−1 (2.77 moles of lithium) at a current density of 0.1 mA cm−2 compared to rest of the adipic acid concentrations. Further, the cell retained 83% of capacity after 50 galvanostatic charge-discharge cycles at ambient conditions. Li-insertion/extraction mechanism and improvement in electronic conductivity profiles are validated through cyclic voltammetry and electrochemical impedance spectroscopy, respectively.