A High Temperature (400 to 650oC) Secondary Storage Battery Based on Liquid Sodium and Potassium Anodes

This project will develop technolgy for integrating a high-temperature (400 to 700ºC), high-efficiency (greater than 90%) secondary battery with a 3 to 10 kW solid oxide fuel cell (SOFC) system. The battery will be based on an alkali-metal-ion-conducting, highly refractory, beta alumina solid electrolyte (BASE) and a non corrosive metal salt. The battery is expected not only to meet or exceed weight and cost targets but also to be superior to the sodium-sulfur battery ¿ which currently has demonstrated over 5,000 charge-discharge cycles, with a lifetime in excess of 7 years and capacity as large as 8 MW. In Phase I, high strength, tubular, and disc-shaped Na-BASE and K-BASE will be fabricated by a patented vapor phase process. Electrochemical couples ¿ with Na and K as the anodes, BASE as the electrolyte, and suitable metal salts as the cathodes ¿ will be fabricated and electrochemically tested. Using the most promising cathode, planar cells will be assembled into a stack, which will be subjected to several charge-discharge cycles. The overall roundtrip efficiency will be measured. Commercial Applications and Other Benefits as described by the awardee: Commercial applications should include: automotive transportation; uninterrupted power sources for the computer, information, and semiconductor industries; an SOFC-battery hybrid for residential use; and distributed power.