Energy storage optimization takes a great deal of wisdom, such as the proper trade-offs between energy density or power density. Batteries, which store energy by separating chemicals and are better for delivering lots of energy, while capacitors, which store energy by separating electrical charges, are better for delivering lots of power (energy per time).
Life would be simpler if both were always available without high cost.
At the AVS 57th International Symposium&Exhibition in Albuquerque, MIT reported on efforts to store energy in thin carbon nanotubes by adding fuel along the length of the tube - chemical energy, which can later be turned into electricity by heating one end of the nanotubes.