Recent Progress with Ethyleneoxy Phosphazenes as Lithium Battery Electrolytes

Abstract

We report here a series of high-conductivity liquid- and gel-electrolytes based on a mixture of ethyleneoxy phosphazenes and propylene carbonate, which have potential applications in lithium battery assembly. Phosphazene compounds are known to be good materials for solid polymer lithium electrolytes and, following that idea, we have developed low-volatility liquid phosphazene electrolytes that maintain 10⁻⁴ S/cm conductivity. A high conductivity of 10⁻³ S/cm can be achieved when polymeric phosphazenes are used as solidifying agents for conventional battery electrolytes. We also report here the fire retardant properties of the materials, which may lead to future use of these materials as fire retardant additives.