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Title: Structural and Electrochemical Characteristics of Ca-Doped “Flower-like” Li 4Ti 5O 12 Motifs as High-Rate Anode Materials for Lithium-Ion Batteries

Doped motifs offer an intriguing structural pathway toward improving conductivity for battery applications. Specifically, Ca-doped, three-dimensional “flower-like” Li 4–xCa xTi 5O 12 (“x” = 0, 0.1, 0.15, and 0.2) micrometer-scale spheres have been successfully prepared for the first time using a simple and reproducible hydrothermal reaction followed by a short calcination process. The products were experimentally characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) mapping, inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge testing. Calcium dopant ions were shown to be uniformly distributed within the LTO structure without altering the underlying “flower-like” morphology. The largest lattice expansion and the highest Ti 3+ ratios were noted with XRD and XPS, respectively, whereas increased charge transfer conductivity and decreased Li +-ion diffusion coefficients were displayed in EIS for the Li 4–xCa xTi 5O 12 (“x” = 0.2) sample. The “x” = 0.2 sample yielded a higher rate capability, an excellent reversibility, and a superior cycling stability, delivering 151 and 143 mAh/g under discharge rates of 20C and 40C at cycles 60 and 70, respectively. In addition, a highmore » cycling stability was demonstrated with a capacity retention of 92% after 300 cycles at a very high discharge rate of 20C. In addition, first-principles calculations based on density functional theory (DFT) were conducted with the goal of further elucidating and understanding the nature of the doping mechanism in this study. The DFT calculations not only determined the structure of the Ca-doped Li 4Ti 5O 12, which was found to be in accordance with the experimentally measured XPD pattern, but also yielded valuable insights into the doping-induced effect on both the atomic and electronic structures of Li 4Ti 5O 12.« less
Authors:
ORCiD logo [1] ;  [1] ;  [1] ;  [2] ; ORCiD logo [2] ;  [3] ; ORCiD logo [2] ;  [2] ; ORCiD logo [3] ; ORCiD logo [2] ; ORCiD logo [2]
  1. Stony Brook Univ., NY (United States)
  2. Stony Brook Univ., NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Report Number(s):
BNL-200081-2018-JAAM
Journal ID: ISSN 0897-4756; TRN: US1802025
Grant/Contract Number:
SC0012704
Type:
Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 30; Journal Issue: 3; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States); Energy Frontier Research Centers (EFRC) (United States). Center for Mesoscale Transport Properties (m2M)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 25 ENERGY STORAGE
OSTI Identifier:
1425064

Wang, Lei, Zhang, Yiman, Guo, Haoyue, Li, Jing, Stach, Eric A., Tong, Xiao, Takeuchi, Esther S., Takeuchi, Kenneth J., Liu, Ping, Marschilok, Amy C., and Wong, Stanislaus S.. Structural and Electrochemical Characteristics of Ca-Doped “Flower-like” Li4Ti5O12 Motifs as High-Rate Anode Materials for Lithium-Ion Batteries. United States: N. p., Web. doi:10.1021/acs.chemmater.7b03847.
Wang, Lei, Zhang, Yiman, Guo, Haoyue, Li, Jing, Stach, Eric A., Tong, Xiao, Takeuchi, Esther S., Takeuchi, Kenneth J., Liu, Ping, Marschilok, Amy C., & Wong, Stanislaus S.. Structural and Electrochemical Characteristics of Ca-Doped “Flower-like” Li4Ti5O12 Motifs as High-Rate Anode Materials for Lithium-Ion Batteries. United States. doi:10.1021/acs.chemmater.7b03847.
Wang, Lei, Zhang, Yiman, Guo, Haoyue, Li, Jing, Stach, Eric A., Tong, Xiao, Takeuchi, Esther S., Takeuchi, Kenneth J., Liu, Ping, Marschilok, Amy C., and Wong, Stanislaus S.. 2018. "Structural and Electrochemical Characteristics of Ca-Doped “Flower-like” Li4Ti5O12 Motifs as High-Rate Anode Materials for Lithium-Ion Batteries". United States. doi:10.1021/acs.chemmater.7b03847.
@article{osti_1425064,
title = {Structural and Electrochemical Characteristics of Ca-Doped “Flower-like” Li4Ti5O12 Motifs as High-Rate Anode Materials for Lithium-Ion Batteries},
author = {Wang, Lei and Zhang, Yiman and Guo, Haoyue and Li, Jing and Stach, Eric A. and Tong, Xiao and Takeuchi, Esther S. and Takeuchi, Kenneth J. and Liu, Ping and Marschilok, Amy C. and Wong, Stanislaus S.},
abstractNote = {Doped motifs offer an intriguing structural pathway toward improving conductivity for battery applications. Specifically, Ca-doped, three-dimensional “flower-like” Li4–xCaxTi5O12 (“x” = 0, 0.1, 0.15, and 0.2) micrometer-scale spheres have been successfully prepared for the first time using a simple and reproducible hydrothermal reaction followed by a short calcination process. The products were experimentally characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) mapping, inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge testing. Calcium dopant ions were shown to be uniformly distributed within the LTO structure without altering the underlying “flower-like” morphology. The largest lattice expansion and the highest Ti3+ ratios were noted with XRD and XPS, respectively, whereas increased charge transfer conductivity and decreased Li+-ion diffusion coefficients were displayed in EIS for the Li4–xCaxTi5O12 (“x” = 0.2) sample. The “x” = 0.2 sample yielded a higher rate capability, an excellent reversibility, and a superior cycling stability, delivering 151 and 143 mAh/g under discharge rates of 20C and 40C at cycles 60 and 70, respectively. In addition, a high cycling stability was demonstrated with a capacity retention of 92% after 300 cycles at a very high discharge rate of 20C. In addition, first-principles calculations based on density functional theory (DFT) were conducted with the goal of further elucidating and understanding the nature of the doping mechanism in this study. The DFT calculations not only determined the structure of the Ca-doped Li4Ti5O12, which was found to be in accordance with the experimentally measured XPD pattern, but also yielded valuable insights into the doping-induced effect on both the atomic and electronic structures of Li4Ti5O12.},
doi = {10.1021/acs.chemmater.7b03847},
journal = {Chemistry of Materials},
number = 3,
volume = 30,
place = {United States},
year = {2018},
month = {1}
}