Ionically Conductive Polyelectrolyte Multilayers for Microbattery Applications

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

The alternating adsorption of polyelectrolytes and other multivalent organic and inorganic species has evolved in the past decade into a quickly developing new field of materials science. The multilayer assembly technique, which involves the alternating adsorption of oppositely charged species from dilute aqueous or mixed solvent solutions, has been used to create a number of systems with electrical, optical, dielectric and electrochemical functionality. Ultrathin films with high uniformity are can be created using layer-by-layer assembly techniques. The ease of fabrication, ability to control film structure on a nanometer length scale, and the tunability of the final properties of the film make polyelectrolyte multilayer approaches interesting as components in micron scale battery applications. Recent work from the Hammond research group has resulted in a number of microfabrication techniques that allow the incorporation of functional polymer multilayers into micron scale devices. New work in this group has also led to orders of magnitude increases in the solid state ionic conductivity of polyelectrolyte multilayer films through the use of highly acidic polyions such as perfluorosulfonated ionomers, and the incorporation of polyethylene oxide. The goals of this work are to develop new polyelectrolyte multilayer systems with ionic conductivities suitable for thin film battery applications, to take advantage of the nanometer scale control that multilayer assembly processes provide to develop electrolyte films with gradient electronic conductivities for battery electrode components, and to apply nonlithographic microfabrication techniques developed in this group to create cheap, easily manufactured multilayer battery devices on plastic, glass or paper substrates for plastic and paper thin film electronics applications.