PEO-based composite polymer electrolytes

Poly(ethylene oxide) (PEO)-based composite polymer electrolytes have been widely studied during the last ten years. At present, systems with room temperature conductivity up to 10−4 ohm−1 cm−1 have been synthesized and tested in electrochemical devices like lithium-ion rechargeable batteries. In this paper, we will chiefly focus on the experimental work, whereas the theoretical models for ion transport will be only summarized. The systems are classified as `blend-based' and `mixed-phase' composite electrolytes. We call blend-based systems those systems obtained from homogeneous solutions of two components in an appropriate common solvent. Mixed-phase systems are inhomogeneous mixtures of polymer and inorganic or organic additives not dissolved in a common solvent. Effective Medium Theories (EMT) are useful for modelling the conductivity behaviour in these composite electrolytes.