In the chart from the article I see that capacitors are shown as having high specific power. Would it not work to use a hybrid approach of capacitors for takeoff and then Li-ion for most of the flight? I know it would make the system more complicated and therefore more expensive up front, but I wonder if it's an option or if it's out of the question for one reason or another. I've read that supercapacitors are being used for busses and other applications. https://en.wikipedia.org/wiki/Supercapacitor