Microstructural, Impedance and Conductivity Studies of Vanadium Substituted Li4Ti5O12 Anode Materials for Li-ion Batteries through Ceramic Method

Abstract

This paper reports the effect of Vanadium (V) substitution in Titanium (Ti) site of spinel lithium titanate (Li₄Ti₅O_12, LTO) negative electrode materials for Li-ion batteries (LIBs) is studied and analysed. A series of anode materials based on the Li₄Ti_5-xV_xO₁₂                    (x=0, 0.0125 and 0.025) are prepared by simple ceramic route at 900 °C for 16 hrs.  Their phase formation processes, crystal structures, morphology, cation distribution and electrical properties were studied using XRD, SEM, FTIR and LCR characterization techniques. The X-ray diffraction (XRD) studies confirmed  thestructure of the materials belonged to cubic spinel group with Fd-3m space group. The topography and morphological structures of phase and distribution of the size of the grains are found to be in the range of 1 to 4 ?m as obtained from SEM analysis.  FTIR studies also  confirmed that the spinel structure in fingerprint region was unchanged when the structure was vanadium doped by 0.025.   The  impedance of         Li₄Ti_5-xV_xO₁₂materials were studied in the frequency ranging from 50 Hz to 1MHz and also in the 30 °C-120 °C range of temperature by employing complex impedance spectroscopy (CIS) method.  However, both V_0.0125LTO and V_0.25LTO doped materials seem to possess good electronic conductivity compared to pure Li₄Ti₅O₁₂.