Effects of Ti Doping on the Structural Stability and Enhanced Electrochemical Performance of α-LiVOPO4

다국어 초록 (Multilingual Abstract)

Lithium vanadyl phosphate has seven different crystallographic phases. Among them, α-LiVOPO4 is chosen because of its relatively high energy density and redox voltage of 3.9 V compared to the other phosphates. In this study, Ti4+-doped α-LiV1?xTixOPO4 (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-LiV1?xTi xOPO4 (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-LiV0.995Ti0.005OPO4 showed the best cycling stability and rate capability among all the samples examined because Ti doping retained its site to prevent structural collapse.

참고문헌 (Reference)

1 P. Barpanda, 21 : 1801-, 2015

2 P. Barpanda, 30 : 772-, 2011

3 J. A. Bearden, 39 : 125-, 1967

4 K. L. Harrison, 26 : 3849-, 2014

5 B. Xu, 73 : 51-, 2012

6 D. Morgan, 7 : A30-, 2004

7 C. J. Allen, 158 : A1250-, 2011

8 D. choi, 163 : 1064-, 2007

9 S. Y. Chung, 1 : 123-, 2002

10 B. M. Azmi, 146 : 525-, 2005

11 K. L. Harrison, 25 : 1751-, 2013

12 A. Tang, 161 : A10-, 2014

13 B. J. Paul, 1 : A63-, 2012

14 K. Saravanan, 21 : 10042-, 2011

15 M. M. Ren, 112 : 13043-, 2008

16 T. A. Kerr, 3 : 460-, 2000

17 Y. Li, 16 : 24604-, 2014

18 C. Ling, 2 : 12330-, 2014

19 Z. Yu, 56 : 8611-, 2011

20 Y.-R. Zhu, 547 : 107-, 2013

21 C.-C. Yang, 258 : 424-, 2014

22 T.-F. Yi, 195 : 285-, 2010

23 L. Wang, 56 : 6906-, 2011

24 Y. Yang, 10 : 1292-, 2008

25 S. De, 68 : 66-, 2007

26 G. Silversmit, 135 : 167-, 2004

27 M. Scrocco, 61 : 453-, 1979

28 S. K. Sen, 39 : 560-, 1975

29 P. Yu, 146 : 8-, 1999

30 "Exafs Materials Reference X-Ray Spectra for Metal Foils" Exafs Materials 1967

31 F. Marken, "Cyclic Voltammetry"

32 Y.-R. Luo, "Bond Dissociation Energies" 69 : 2009