Comparative performance assessment of Li batteries with solid and highly concentrated electrolytes for aviation applications

Non-flammable next-generation batteries with high power and energy density are essential to meet the high demands of aircraft applications. These cells require electrolytes that not only are stable but that also ensure reliable battery performance under dynamic load conditions. This study employs a physicochemical model to evaluate and compare the electrochemical performance of cells using different cathodic electrolytes: hybrid solid electrolytes, highly concentrated liquid electrolytes, and ionic liquids (ILs). To isolate the intrinsic behavior of each electrolyte under ideal conditions, the evaluation deliberately excludes side reactions, interfacial stability, and contact limitations, focusing solely on gravimetric energy, power output, and mission performance theoretically achievable with such cells. Cells with LiFSI as salt, IL-hydrofluoroether (HFE) as cathode electrolyte or with LiFSA as salt and sulfolane-HFE show superior performance and require less battery mass for aircraft use. To meet the mission requirements of a regional aircraft configuration and when assuming ideal conditions, cathode thicknesses of 70 μm, 60 μm, and 40 μm for sulfolane-HFE, IL-HFE, and hybrid solid electrolytes, respectively, were determined. This approach helps to identify promising electrolyte candidates, exclude stable candidates that cannot fulfil the dynamic power demand, reduce unnecessary experimental efforts, and support the development of efficient and safe battery systems for aviation.