Interest in broadband dielectric spectroscopy to study the electronic transport in materials for lithium batteries

• Published in: Materials science & engineering. B, Solid-state materials for advanced technology Vol. 213; pp. 190 - 198
• Main Authors: Badot, Jean-Claude, Lestriez, Bernard, Dubrunfaut, Olivier
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.11.2016; Elsevier BV; Elsevier
• Subjects: Agglomerates; Batteries; Broadband; Charge density; Coated electrodes; Complex permittivity; Composite electrodes; Conduction; Conductors; Dielectric relaxation; Dielectric spectroscopy; Dielectrics; Electrodes; Electron transport; Electronic conductivity; Engineering Sciences; Fluctuation; Interfaces; Lithium; Lithium batteries; Materials; Multiscale conductivity and permittivity; Particulate composites; Spectroscopic analysis; Interfaces; Multiscale conductivity and permittivity; Lithium batteries; Dielectric spectroscopy; Electronic conductivity; Composite electrodes
• ISSN: 0921-5107; 1873-4944
• DOI: 10.1016/j.mseb.2016.05.012

•Broadband dielectric spectroscopy measures the multiscale electronic conductivity from macroscopic to interatomic sizes.•There is an influence of the surface states on the electronic transfer of powdered materials (e.g. thin insulating layer of Li2CO3 on LiNiO2 and carbon coating on LiFePO4).•Electrical relaxations resulting from the interfacial polarizations at the different scales of the carbon black network are evidenced. Broadband dielectric spectroscopy (BDS) is used to measure complex permittivity and conductivity of conducting materials for lithium batteries at frequencies from a few Hz to several GHz with network and impedance analysers. Under the influence of an electric field, there will be charge density fluctuations in the conductor mainly due to electronic transfer. These fluctuations result in dielectric relaxations for frequencies below 100GHz. The materials are compacted powders in which each element (particles, agglomerates of particles) can have different sizes and morphologies. In the present review, studies are reported on the influence of surface states in LiNiO2 (ageing and degradation in air) and LiFePO4 (carbon coating thin layer), and on a composite electrode based on the lithium trivanadate (Li1.1V3O8) active material. The results have shown that the BDS technique is very sensitive to the different scales of materials architectures involved in electronic transport, from interatomic distances to macroscopic sizes.