Novel Lithium-Ion Conducting Polymer Electrolytes for Lithium-Ion Batteries

60177 Polymer electrolytes that promote lithium ion activity are needed to develop advanced batteries for high power or high energy storage. Polymers should be thin and flexible with glass transition below -70¿C and ionic conductivity >10-3 S/cm. In this project, new carbonate side chains will be introduced into the carbonate-siloxane polymer matrix to increase the ionic conductivity to 10-3S/cm. New lithium salts and crosslinkers will also be evaluated to enhance the ionic conductivity. During Phase I, synthetic methods were developed to incorporate the allyl carbonate side chains into the polysiloxane backbone. This resulted in a thin, flexible polymer with an ionic conductivity of 2.75 x 10-4 S/cm. Various ratios of carbonate to siloxane, siloxane to crosslinker, and carbonate to Li+ were evaluated to achieve the desired results. Phase II will evaluate several more carbonate side chains using methods developed in Phase I. New lithium salts and crosslinkers will be evaluated. A method will be developed for incorporating the carbonate-siloxane polymer in a cathode matrix, which will be integrated in a battery for extensive performance evaluation. Commercial Applications and Other Benefits as described by the awardee: Commercial applications include high energy batteries for electric and hybrid vehicles, field-useable test equipment. The polymer electrolytes could also be utilized for development of battery technologies for consumer products such as cell phones, computers, and video equipment.