Fabrication and Performance of Li-S/Se Solid State Cathodes with Holey Graphene As a Conductive Scaffold and Binder

Electric aircraft demonstrate potential as the future of aviation, offering zero emissions, lower noise, and potentially lower operational costs than aircraft powered by internal combustion engines. Currently, state-of-the-art lithium (Li) ion batteries used to enable today’s electrical vehicles lack the specific energy (< 250 Wh/kg) required to make electric flight (ideally requiring >400 Wh/kg) an economically beneficial endeavor. Additionally, Li ion batteries introduce serious safety concerns due to the highly flammable organic liquid electrolytes contained within the cell. Li-sulfur/selenium (Li-S/Se) cell chemistries possess high theoretical energy densities (2600 and 1160 Wh/kg, respectively) and therefore are a promising option to power electric aircraft. Rings of S doped with Se as the active cathode material result in a cell electrochemistry that can provide a balanced energy and power output during their reaction with Li. To improve safety, the S/Se cathode can be implemented with a solid-state electrolyte (SSE) to ensure the batteries would not be flammable. However, there are tremendous challenges in optimizing the interface between SSEs and the active material in the cathode composite to achieve desirable performance. In this presentation, we report our findings on the cathode fabrication and performance for solid-state Li-S/Se battery cells. We demonstrate that holey graphene (hG), a structural derivative of graphene, can serve as a scaffold host and binder to facilitate the close contact between the active material and SSEs. In addition, hG has unique properties such as through plane holes and dry compressibility that can aid in the fabrication and electrochemical performance of these high energy density solid-state batteries.