Energy Storage Systems for Very High Altitude Very Long Endurance Solar Aircraft

The Lithium-oxygen electrochemical couple has the potential to form the basis of a very high specific energy, rechargeable battery for the very high altitude, very long endurance solar aircraft. Recent progress in the application of non-aqueous electrolytes to realize the benefits of this chemistry has resulted in limited success in terms of providing a long endurance, regenerative system. We propose to investigate a variety of approaches to improve the cycle life, reliability, and safety of the Lithium-oxygen battery, both in an oxygen atmosphere and in an “air breathing” mode. Our work on improving the performance characteristics of the Lithium-oxygen/Lithium-air battery will focus on the implementation of a solid state, Lithium ion electrolyte in the battery to provide a stable interface with both the anode and cathode to control passivation phenomena at the electrodes, promote good morphology of redeposited Lithium metal during charging, and protect the anode from chemical reaction with the cathode reactant. Polymer(s) or ceramic/glass electrolytes will be the choice for the solid state electrolytes, and may be used in conjunction with liquid electrolytes. In addition, the application of ionic liquid based electrolytes in the Lithium-oxygen battery technology will be explored. Furthermore, we will maintain adequate power density in the battery despite the introduction of solid-state Li+ conductors in the battery through interface engineering.