Publication

Abstract : Spinel Li4Ti5O12 (LTO) exhibit high power but low capacity of 175 mAh/g with discharge cut-off limit of 1.0 V. Higher capacity of Li4Ti5O12 is possible by deep discharge below 1.0 V, which can enhance the full-cell energy density. Herein, we focus on a large-scale synthesis of LTO by a hydrothermal process obtaining nanosheets investigated for its structural, morphological and surface chemical properties. The electrochemical studies were conducted varying the lithiation voltage limit cut-off to 1.0, 0.5 and 0.05 V delivering reversible capacity of 159, 200 and 285 mAh/g respectively, good rate capability up to 1750 mA/g delivering capacity > 150 mAh/g and above 70 % retention at the end of 2000 cycles at all cut-off limits. In addition to deep discharge, the LTO has been tested for its low temperature (−15 °C) performance at these cut-off limits. The deeper insights into the electrochemical behavior has been understood by electrochemical impedance spectroscopy and cyclic voltammetry. Further, structural and surface chemical changes during first cycle at room temperature and low temperature have been investigated by ex-situ X-ray diffraction and X-ray photoelectron spectroscopy. We have systematically studied the behavior of LTO anode at deep discharge and at low temperature conditions for the first time.