Electroactive Polymer Coating for Improved Battery Safety

Physical Sciences Inc. (PSI) proposes to form an electrochemical switch to prevent catastrophic failure in lithium-ion batteries by coating the cathode material with an electroactive polymer. The electroactive polymer can be reversibly “switched” from an insulator to a conductor upon oxidation permitting high rate capability during normal operation. In Phase I, PSI will demonstrate that upon a short or overdischarge the polymer reversibly switches to an insulator reducing the current flow to the cathode material. This reduced current flow will be demonstrated to decrease the localized heat generation by more than two orders of magnitude. PSI will also demonstrate that insulation of the cathode material limits irreversible degradation of the discharge capacity upon overdischarge maintaining cell balance and improving cycle life. In the Phase II program, we will scale up the coating procedure to produce cathode material on a production scale and demonstrate the technology in a 5Ah battery.