Effect of the Niobium Doping Concentration on the Charge Storage Mechanism of Mesoporous Anatase Beads as an Anode for High-Rate Li-Ion Batteries
Journal article, 2021

A promising strategy to improve the rate performance of Li-ion batteries is to enhance and facilitate the insertion of Li ions into nanostructured oxides like TiO2. In this work, we present a systematic study of pentavalent-doped anatase TiO2 materials for third-generation high-rate Li-ion batteries. Mesoporous niobium-doped anatase beads (Nb-doped TiO2) with different Nb5+ doping (n-type) concentrations (0.1, 1.0, and 10% at.) were synthesized via an improved template approach followed by hydrothermal treatment. The formation of intrinsic n-type defects and oxygen vacancies under RT conditions gives rise to a metallic-type conduction due to a shift of the Fermi energy level. The increase in the metallic character, confirmed by electrochemical impedance spectroscopy, enhances the performance of the anatase bead electrodes in terms of rate capability and provides higher capacities both at low and fast charging rates. The experimental data were supported by density functional theory (DFT) calculations showing how a different n-type doping can be correlated to the same electrochemical effect on the final device. The Nb-doped TiO2 electrode materials exhibit an improved cycling stability at all the doping concentrations by overcoming the capacity fade shown in the case of pure TiO2 beads. The 0.1% Nb-doped TiO2-based electrodes exhibit the highest reversible capacities of 180 mAh g-1 at 1C (330 mA g-1) after 500 cycles and 110 mAh g-1 at 10C (3300 mA g-1) after 1000 cycles. Our experimental and computational results highlight the possibility of using n-type doped TiO2 materials as anodes in high-rate Li-ion batteries.

DFT calculation

Rietveld refinement

mesoporous niobium doped anatase

n-type doped anode materials

high-rate batteries

Li-ion batteries

Author

Carmen Cavallo

Chalmers, Physics, Materials Physics

University of Oslo

Giulio Calcagno

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Applied Surface Chemistry

Rodrigo Pereira De Carvalho

Uppsala University

Matthew Sadd

Chalmers, Physics, Materials Physics

Bruno Gonano

University of Oslo

C. Moyses Araujo

Uppsala University

Anders Palmqvist

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Applied Surface Chemistry

Aleksandar Matic

Chalmers, Physics, Materials Physics

ACS Applied Energy Materials

25740962 (eISSN)

Vol. 4 1 215-225

Subject Categories

Inorganic Chemistry

Materials Chemistry

Other Chemical Engineering

DOI

10.1021/acsaem.0c02157

More information

Latest update

2/28/2021