Premium
Effects of Ti Doping on the Structural Stability and Enhanced Electrochemical Performance of α‐LiVOPO 4
Author(s) -
Lee SeongHun,
Ryu KwangSun
Publication year - 2018
Publication title -
bulletin of the korean chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.237
H-Index - 59
ISSN - 1229-5949
DOI - 10.1002/bkcs.11586
Subject(s) - x ray photoelectron spectroscopy , analytical chemistry (journal) , cyclic voltammetry , triclinic crystal system , materials science , fourier transform infrared spectroscopy , electrochemistry , lithium (medication) , spectroscopy , chemistry , electrode , crystal structure , crystallography , nuclear magnetic resonance , chemical engineering , medicine , physics , chromatography , quantum mechanics , engineering , endocrinology
Lithium vanadyl phosphate has seven different crystallographic phases. Among them, α‐LiVOPO 4 is chosen because of its relatively high energy density and redox voltage of 3.9 V compared to the other phosphates. In this study, Ti 4+ ‐doped α‐LiV 1− x Ti x OPO 4 ( x = 0.00, 0.003, 0.005, 0.007, and 0.01) was prepared using a sol–gel method to increase the structure stability and electrochemical performance. The triclinic structure with the space group P ‐1 was confirmed by X‐ray diffraction, Fourier‐transform infrared spectroscopy, and X‐ray photoelectron spectroscopy. Inductively coupled plasma–optical emission spectroscopy was conducted to determine the precise state. The shape and size of the particles were observed by field‐emission scanning electron microscopy. In situ X‐ray absorption spectroscopy was performed to confirm the structural behavior during the electrochemical reaction. Electrochemical measurements such as cyclic voltammetry and galvanostatic charge–discharge were conducted. α‐LiV 1− x Ti x OPO 4 ( x = 0.003, 0.005, 0.007, and 0.01) showed structural stability during cycling as well as decreased polarization during charge and discharge with the increased diffusion coefficient of lithium ions. α‐LiV 0.995 Ti 0.005 OPO 4 showed the best cycling stability and rate capability among all the samples examined because Ti doping retained its site to prevent structural collapse.