Novel Materials for Fuel Cells and Batteries Light Scattering Studies of the Structure and Dynamics of Polymer Electrolytes

Abstract: The development of new materials and technologies for electrochemical energy conversion and storage, such as fuel cells and batteries, is important for a future more efficient use of energy. Polymer electrolytes are key components in polymer electrolyte fuel cells and lithium-based batteries. A better understanding of the materials properties is needed to optimise materials for each application. This thesis includes reports of three types of polymer electrolytes. Micro-Raman spectroscopy was used to study the structure and composition of fuel cell membranes consisting of poly(styrene sulfonic acid) grafted onto a partially or completely fluorinated polymer matrix, mainly poly(vinylidene fluroide). In focus was the spatial distribution of functional groups controlling proton transport and influencing mechanical properties. Fuel cell tested membranes were studied to find the reasons for membrane failure and how the structure affects the membrane life-time in a fuel cell. The effects of polymer end-groups on salt solvation in a polymer/salt complex was investigated with Raman spectroscopy. The interactions and charge carriers in novel acid doped gels were studied with vibrational spectroscopy and the dynamics of acid and salt doped gel electrolytes with a liquid electrolyte of ethylene carbonate/ propylene carbonate and a poly methyl methacrylate polymer matrix were investigated with photon correlation spectroscopy.