Variation of Ti Valence with Lithium Content in Lithiated/Delithiated Li4Ti5O12 Studied by X-Ray Absorption near the Edge Structure
YU Peng-Fei1, CUI Zhong-Hui1, MENG Jian-Wei2, GUO Xiang-Xin1**
1State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 2State Key Laboratory of ASIC and System, Department of Microelectronics, Fudan University, Shanghai 200433
Abstract：Synchrotron-based x-ray absorption near-edge structure (XANES) spectroscopy is applied to investigate the variation of Ti valence in the discharge and charge processes of Li4Ti5O12. Through analysis of the XANES data, the average valence of Ti can be calculated, which allows quantitative determination of the ratios of Ti3+/Ti4+ as a function of Li content in the electrodes. It is found that the ratios in the composites of Li4Ti5O12/acetylene black (AB)-carbon are larger than those in Li4Ti5O12/Ag/AB-carbon after the discharge to 1.1 V, indicating a larger amount of Li inserted into the former than that into the latter. This finding provides a good explanation for the fact that the Li4Ti5O12/AB-carbon samples exhibit larger storage capacities than the Li4Ti5O12/Ag/AB-carbon ones prepared in this work, concerning the larger Ti3+/Ti4+ ratio and the larger amount of Li+ inserted in the electrode for satisfying the charge neutralization requirement.
(Energy storage systems, including capacitor banks)
引用本文:
. [J]. Chin. Phys. Lett., 2013, 30(3): 36102-036102.
YU Peng-Fei, CUI Zhong-Hui, MENG Jian-Wei, GUO Xiang-Xin. Variation of Ti Valence with Lithium Content in Lithiated/Delithiated Li4Ti5O12 Studied by X-Ray Absorption near the Edge Structure. Chin. Phys. Lett., 2013, 30(3): 36102-036102.
2013, Vol. 30 
