One of these days, some cleverclogs is going to present to the press a black box that stores electrical charge (and even gives back almost all of it when asked

One of these days, some cleverclogs is going to present to the press a black box that stores electrical charge (and even gives back almost all of it when asked politely) with an energy density almost as good as liquid fuels. If he can shut up about it containing liquid fuels that are synthesized on the spot, they'll eat it up and hail the finding of the battery holy grail.