6 - Polymer electrolytes II: Physical principles

Summary

Introduction

Within the field of electrochemistry the topic of electrolytes, that is the study of salts dissolved in solvents, is regarded by some as a mature discipline. It is viewed as less exciting than its sister topic of electrodics, which is concerned with the interface between electrolytes and electrodes; however, this is far from true for solid polymer electrolytes. These materials consist of salts dissolved in a solid, coordinating, polymeric solvent. They were first investigated by Fenton, Parker and Wright (1973) and have been intensively studied since Armand (1978) recognised their unique potential as electrolytes with a ‘solid-solvent’. In recent years many such electrolytes have been prepared. An introduction to polymer electrolytes including a discussion of the different systems is presented in the preceding chapter by Shriver and Bruce. A sufficient body of knowledge has now accumulated on polymer electrolytes to permit the establishment of the fundamental physical principles on which such materials are based. It is with the physical aspects of solid polymer electrolytes that this chapter deals and in this sense it differs from the previous chapter.

Our fundamental understanding of polymer electrolytes is derived from both the general examination of a wide range of distinct electrolytes and from some very detailed studies of a few model systems.