Materials Research Activities

Solid state batteries intro

Solid-state Batteries

Solid-state batteries have some distinct advantages over those with a liquid electrolyte. The main one is the avoidance of electrolyte leakage into the electrodes with the attendant danger of chemical reactions that damage their performance, and also miniaturization, for example in a thin-film form. Solid-state batteries are long-lived and inherently safer. They can be used in both low-power and high-energy forms. They can combine two functions: separating the electrodes and conducting the ions.

Rapid motions of ions in solids had been noticed in a few individual materials such as zirconium oxide, silver iodide and beta-alumina before the period that we are concerned with here. Particularly important was the latter. The discovery of the potential of this inexpensive and easily synthesized material as a promising solid electrolyte by Ford Company Researchers in 1967 (read their paper here) prompted research on other materials. There is a widespread consensus that in 1973 a new research community came into being with a conference on Fast Ion Transport in Solids. This interdisciplinary field was later renamed Solid State Ionics. You can read an introduction to the technical matter in solid state ionics here.

The central feature of this field is the combination of fundamental studies and applied research. Fundamental studies involve chemists working to invent new materials (e.g. titanium disulfide to a large extent developed by Stanley Whittingham) with structures promoting high ionic conductivity at low (ambient) and moderate temperatures and physicists who try to understand the mechanisms of fast ionic diffusion in solids on structural and thermodynamic basis. Applied research is devoted to the development of fuel cells or solid-state batteries for electric vehicles, and to other applications such as power levelling or electrochromic materials or oxygen sensor.

An international research community of several hundred researchers working in academic or industrial laboratories has formed, in Europe, in the USA and in Japan. It expanded the field initially confined to the study of solid electrolytes so as to include the study of mixed (ionic and electronic) conductors with variable chemical composition such as lithium-intercalated titanium disulfide for solid electrodes in order to develop all-solid batteries. A turning point is the discovery that organic polymers can exhibit high ionic conductivity as well. Much of this research has been done in France, and you can read interviews of several of the important individuals there: Armand, Barboux, Boilot, Gauthier (in Canada), Griesemann, and Livage.

The future of this dynamic branch of material science thus remains dependent on environmental policies and public attitudes toward energy consumption. Or does not it? Do tell us what you think, for instance in the context of the following discussion groups:

This page was written by Hervé Arribart, Bernadette Bensaude-Vincent and Arne Hessenbruch. It was last updated by Arne Hessenbruch on 15-Feb-2001.