Safe, High Energy Batteries for Space Suits

A new generation of spacesuits is needed to support EVAs for future surface exploration missions. These new suits will require decreased mass and volume, improved functionality, and excellent reliability. More power is required than today’s suit can provide. The battery pack will be the main source of power and weight and needs to provide an energy source for life-support functions, communications, system health status, and other needs. In addition, the battery must operate safely under harsh conditions of extreme temperatures, mechanical injury, and tolerate radiation. NOHMs Technologies is proposing to develop ionic liquid based hybrid electrolytes for safe, high energy density, high voltage, and high power batteries for space suit applications.NOHMs will develop a safe electrolyte for LiCoO2 that prevents thermal runaway and allows LiCoO2 to be charged at a higher voltage resulting in higher capacity. Rechargeable lithium ion batteries (Li-ion) are promising energy storage options for space applications. When charged to 4.2V LiCoO2 delivers 140 mAh/g specific capacity, which is only 51% of the theoretically possible (272 mAh/g) based on the crystal structure and allowable Li-ions it can host. To extract the unutilized capacity from the LiCoO2, one has to electrochemically activate the cathode by charging to a potential > 4.5 V vs Li/Li+. It has been shown that the high voltage charging of LiCoO2 results in 28% increase in delivered capacity and 4% increase in the nominal voltage. However, conventional Li-ion battery electrolytes are not stable at such high voltages and complementary development of electrolytes that are stable at these voltages are needed. In this Phase I, we will design electrolytes with functional ionic liquids and co-solvents to enable a high voltage, thermally stable and electrolyte formulation for traditional LiCoO2 cathode materials.