KY EPSCoR: A Low Temperature Flow Battery Prototype for Space Applications

While low-temperature-tolerant energy storage systems are of interest for application in extreme environments on Earth, our interest lies in the development of battery technologies for use in probes in space, particularly in the mission to send a probe to Jupiter's moon Europa, which contains a watery ocean world undrneath its icy surface. Having batteries that tolerate lower temperatures would allow for less insulation to keep batteries warm, which could reduce the mass of all components required to store charge. Here we seek to develop a prototype low-temperature redox flow battery (RFB) containing organic electro-active materials developed at the University of Kentucky: a one-electron-donating phenothiazine created in the Odom group will serve as the posolyte, and a two-electron-accepting quinone created in the Anthony group will serve as the negolyte. Aiming for concentrations of at least 0.5 M for the posolyte and at least 0.25 M for the negolyte at temperatures of at least as low at -40 ºC, we will perform cycling tests of the materials in a prototype to determine performance metrics and limitations, which will better enable us to improve components - whether anolyte/posolyte, eletrolyte salts and solvents, or RFB components or parts of the flow cell - to improve system performance. In additon to scale-up efforts in synthesis required to produce sufficient quantities of materials for cycling experiments, Anthony will explore the synthesis of new materials that may serve as even more highly soluble negolytes, and in some cases mateirals that would serve as both the electron donor and electron acceptor, which could enable the fabrication of a symmetric cell.