Broadband impedance spectroscopy of Li₄Ti₅O₁₂

from nearly constant loss effects to long-range ion dynamics

authored by

Bernhard Gadermaier, Katharina Hogrefe, Paul Heitjans, H. Martin R. Wilkening

Abstract

Li₄Ti₅O₁₂ (LTO) is known as one of the most robust and long-lasting anode materials in lithium-ion batteries. As yet, the Li-ion transport properties of LTO are, however, not completely understood. Here, we used broadband impedance spectroscopy spanning a wide temperature range to investigate the full electrical response of LTO over a wide frequency range. It turned out that the isotherms recorded entail information about two relaxation processes. While at high temperatures the isotherms show a frequency independent plateau that corresponds to poor long-range ion transport (<10⁻¹¹ S cm⁻¹ (298 K), 0.79 eV), they reveal a second region, seen at lower temperatures and higher frequencies, which we attribute to short-range ion dynamics (10⁻⁸ S cm⁻¹) with a significantly reduced activation energy of ca. 0.51 eV. At even lower temperatures, the isotherms are fully governed by nearly constant loss behavior, which has frequently been explained by cage-like dynamics. The present results agree with those earlier presented by ⁷Li NMR spin-lattice relaxation measurements being sensitive to dynamic processes taking place on quite different length scales. Our findings unveil complex Li⁺ ion dynamics in LTO and help understand its superior electrochemical properties.

Organisation(s)

Institute of Physical Chemistry and Electrochemistry

External Organisation(s)

Graz University of Technology

Type

Article

Journal

Zeitschrift fur Anorganische und Allgemeine Chemie

Volume

647

Pages

2167-2171

No. of pages

5

ISSN

0044-2313

Publication date

12.11.2021

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Inorganic Chemistry

Sustainable Development Goals

SDG 7 - Affordable and Clean Energy

Electronic version(s)

https://doi.org/10.1002/zaac.202100143 (Access: Open)