Car battery (varta e44 77Ah) Weight 18 kg. Usable energy stored 2.21MJ. 18 kg Jet A1 or gasoline: 803MJ of usable energy.
Going any fancy battery (lithium ion) will do x2 energy x10 price for the same weight. Best commercial battery in the world x3 energy, x100 price.
I know you don't believe me, but these are the facts. You need roughly 100 times the weight in fuel (because electric engines extract energy from batteries roughly 2x better than piston engines from fuel). So if you load 120kg of gas in your cessna 172 to do a trip, you would need 12000kgs (yes, 12 tons) of batteries to do the same trip. Only now of course you need an A318 to lift the batteries.
To sum it up, if you retrofit an airbus 318 with half a million $ worth of batteries (12000kg) and you find someone to donate two electric engines with enough thrust, you end up with a theoretical range of 57km.
As of today, we produce electricity basically burning stuff. In cars, regen braking and all, you produce the same CO2 with an electric car than with a petrol one. They make a little sense because you take pollution away from city center.
But in planes, where wheels do not happily cancel the weight penalty at constant speed, the idea is crazy beyond belief. Completely derailed.