Improve the low-temperature electrochemical performance of Li 4 Ti 5 O 12 anode materials by ion doping
- PDF / 2,210,421 Bytes
- 11 Pages / 595.276 x 790.866 pts Page_size
- 6 Downloads / 208 Views
Improve the low-temperature electrochemical performance of Li4Ti5O12 anode materials by ion doping Chunlin Li1, Qian Huang1, and Jian Mao1,* 1
College of Materials Science and Engineering, Sichuan University, 610065 Chengdu, Sichuan, China
Received: 20 July 2020
ABSTRACT
Accepted: 12 October 2020
We adopt the strategy of doping ions of Mg2?, Cr3?, and F- into Li4Ti5O12 (LTO) to substitute Li, Ti, and O, respectively (called the corresponding sample MgLTO, Cr-LTO, and F-LTO, respectively), and investigated its influences on the low-temperature electrochemical performance of LTO. After doping, the electrical conductivity of Mg-LTO, Cr-LTO, and F-LTO increased from less than \ 10- 13 S cm- 1 to 3.07 9 10- 7 S cm- 1, 5.57 9 10- 7 S cm- 1, and 7.04 9 10- 7 S cm- 1, respectively. Structural refinement shows that doping has little effect on the radius of the crystal diffusion sites. Further research shows that the main reason for the improvement of low-temperature electrochemical performance is that doping affects the electrical conductivity, micromorphology, and phase composition of LTO. At -20 °C/10 C (1C corresponding to 175 mAh g- 1), the discharge capacities of Mg-LTO, Cr-LTO and, F-LTO are 113 mAh g- 1, 123 mAh g- 1, and 128 mAh g- 1, respectively. As a contrast, there is no discharge capacity for Pure LTO at the same conditions. After 600 cycles at -20 °C/5C, the discharge capacities of the sample of Pure LTO, Mg-LTO, Cr-LTO, and F-LTO are 69.7 mAh g- 1, 107.5 mAh g- 1, 142.3 mAh g- 1, and 133.2 mAh g- 1, respectively. Mg-LTO, Cr-LTO, and F-LTO exhibit excellent low-temperature rate performance and cycling stability. The related electrochemical factors and materials structure mechanisms involved were discussed in detail.
Ó
Springer Science+Business
Media, LLC, part of Springer Nature 2020
1 Introduction It is widely believed that Li4Ti5O12 (LTO) is an ideal material to replace carbon materials as Lithium-ion batteries (LIBs) anode material due to its stable crystal structure about the change of 0.1% in the lattice parameter during the charge/discharge process, high charge/discharge platform about 1.55 V avoiding the
Address correspondence to E-mail: [email protected]
https://doi.org/10.1007/s10854-020-04658-z
formation of lithium dendrites and the decomposition of electrolyte [1, 2]. These merits guarantee that LIBs based on LTO anode materials have excellent security capability and cycling stable performance. Recently, modification methods such as reducing particle size, coating conductive materials, doping ions, and synthesizing two-phase composites have successfully improved the electrical conductivity, lithium diffusion coefficient and specific capacity of
J Mater Sci: Mater Electron
LTO [3–7]. However, its undesirable low-temperature electrochemical performance is one of the factors restricting its practical application [8]. Few reports involve improving the performance of lithium titanate at low temperatures [9–11]. Tao Yuan et al. [12] synthesized a kind of carbon-coated LTO with the capacity
Data Loading...
