[jpt4]

Liquid petrochemicals will continue to be used in any application dominated by power-to-weight ratio considerations.

> Pairing lithium and ambient oxygen can theoretically lead to electrochemical cells with the highest possible specific energy. Indeed, the theoretical specific energy of a non-aqueous Li–air battery, in the charged state with Li2O2 product and excluding the oxygen mass, is ~40.1 MJ/kg = 11.14 kWh/kg of lithium. This is comparable to the theoretical specific energy of gasoline, ~46.8 MJ/kg.

However, electric motors will also continue to improve, and are already the choice when a flat torque curve dominates the design space. Thus, the convergence of these trends (battery performance asymptotically approaching that of gasoline + improved motors and motor control) is the Series Electric Hybrid, with an ICE or fuel cell generator powering an electric power train, with a battery buffer to keep load on the generator constant. This will allow extreme optimization of the generator, so that it perpetually operates at peak efficiency.

[bryanlarsen]

> Liquid petrochemicals will continue to be used in any application dominated by power-to-weight ratio considerations.

Long distance air travel is pretty much the only scenario where this is relevant.