TY - JOUR

T1 - Effect of Mechanical Activation and Carbon Coating on Electrochemistry of TiNb2O7 Anodes for Lithium-Ion Batteries

AU - Kosova, Nina V.

AU - Tsydypylov, Dmitry Z.

N1 - Funding Information: Funding: The authors thank the Ministry of Science and Higher Education of the Russian Federation within the governmental order for the Institute of Solid State Chemistry and Mechanochemistry SB RAS (project FWUS-21-0006) for partial support of this work. Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2022/6

Y1 - 2022/6

N2 - TiNb2O7 anode material with a Wadsley–Roth crystallographic shear structure was prepared by solid-state synthesis at a relatively low temperature (1000◦C) and a short calcination time (4 h) using preliminary mechanical activation of the reagent mixture. The as-prepared final product was then ball milled in a planetary mill with and without carbon black. The crystal structure and morphology of the samples were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Electrochemical performance was studied in a galvanostatic mode in varied voltage intervals and at different cycling rates in combination with in situ electrochemical impedance spectroscopy (EIS) measurements. The resistance measured using in situ EIS had the highest values at the end of the discharge and the lowest when charging. The lithium diffusion coefficient, determined by galvanostatic intermittent titration technique (GITT), in samples milled with and without carbon black was an order of magnitude higher than that for the pristine sample. It was shown that improved electrochemical performance of the carbon composite TiNb2O7/C (reversible capacity of 250 mAh g−1 at C/10 with Coulomb efficiency of ~99%) was associated with improved conductivity due to the formation of a conductive carbon matrix and uniform distribution of submicron particles by size.

AB - TiNb2O7 anode material with a Wadsley–Roth crystallographic shear structure was prepared by solid-state synthesis at a relatively low temperature (1000◦C) and a short calcination time (4 h) using preliminary mechanical activation of the reagent mixture. The as-prepared final product was then ball milled in a planetary mill with and without carbon black. The crystal structure and morphology of the samples were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Electrochemical performance was studied in a galvanostatic mode in varied voltage intervals and at different cycling rates in combination with in situ electrochemical impedance spectroscopy (EIS) measurements. The resistance measured using in situ EIS had the highest values at the end of the discharge and the lowest when charging. The lithium diffusion coefficient, determined by galvanostatic intermittent titration technique (GITT), in samples milled with and without carbon black was an order of magnitude higher than that for the pristine sample. It was shown that improved electrochemical performance of the carbon composite TiNb2O7/C (reversible capacity of 250 mAh g−1 at C/10 with Coulomb efficiency of ~99%) was associated with improved conductivity due to the formation of a conductive carbon matrix and uniform distribution of submicron particles by size.

KW - carbon coating

KW - EIS

KW - galvanostatic cycling

KW - mechanical activation

KW - TiNbO

KW - TiNb2O7

UR - http://www.scopus.com/inward/record.url?scp=85132436300&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/08727a80-196c-3f89-8e96-3c2100f2aa21/

U2 - 10.3390/batteries8060052

DO - 10.3390/batteries8060052

M3 - Article

AN - SCOPUS:85132436300

VL - 8

JO - Batteries

JF - Batteries

SN - 2313-0105

IS - 6

M1 - 52

ER -