Well, those indicators that are now achieved in lithium-ion batteries, for example, on the basis of a cathode using cobalt oxide or a three-core cathode based on Nickel, manganese and cobalt, are resting on the bar of the order of 200-250 watts*hour/kg using carbon anodes.
Of course, electrochemistry is much wider and the number of inorganic active components is much more than you might imagine. For example, the guys from Stanford took as a basis an electrochemical pair of sodium, which is actually almost 2 times worse than lithium. However, due to the fact that they managed to find a cool compound, which includes as much as 4 sodium atoms instead of 1 as lithium-cobalt oxide, the energy consumption of the battery increased significantly.
Our Western colleagues, to put it mildly, 'swung' when they not only began to develop a new cathode, but also began to work with a new anode based on phosphorus. Phosphorus is very active and would rather destroy everything inside the battery than react with sodium and the cathode.
We consider the Stanford University project to be very promising, because the indicators they have already announced are at least 4 (!!!) times higher in finished battery compared to current lithium-ion technology. All this suggests that the era of aircraft is not so far off.