KY EPSCoR: Direct Imaging of Li-ion Nanobattery Cycling at Ambient and Elevated Temperatures

Battery technology is of crucial importance to the future of space operations, since equipment designed to operate in space must be able to collect solar energy during periods of sunlight, and store it for use during darkness. Li-ion batteries are of particular interest due, among other reasons, to their superior energy density, non-toxic and lightweight components, and longevity.1 Recent breakthroughs in Li-ion battery technology include the use of nanostructured components to increase the active area and reduce the volume effect of fracture,2 and fully solid-state battery cells, to increase the safety of operation, especially at high temperature.3,4 We propose to develop a technique to observe the effect of the charge/discharge process in a nano-scale Li-ion battery, to observe changes in microstructure for the first time in the cathodic region. Nanostructured LiCoO2 - a prototypical cathodic material - will be observed in situ, and the size dependence of fracture discerned using a variety of nanowire diameters. Further, our technique should be widely applicable to any new electrode material currently under development and is therefore of great future interest. Finally, the effect of cycling the nanobattery at elevated temperatures will be investigated by repeating in situ device tests at the increased temperatures potentially experienced by power sources traveling to, and operating outside of the Earth's atmosphere.