A quick search shows gasoline has 36,000 watts per litre. So, it is about a third as productive, assuming that the other problems don’t exist.
Such as getting 1/10 the mileage during winter.
You NEVER need to talk the customer into buying something that is just as good or better and if it’s only just as good, at a better price.
The market decides in the end.
Unless you’re Tesla :)
Can you send us a picture of your gasoline-powered phone?
Keep in mind that an ICE burning gasoline has about 30% thermodynamic efficiency, so -- in terms of usable energy to, e.g., drive a car -- it's in the ballpark.
If you were worrying about gas tank size, the energy density of gasoline would be a worthy issue. However, it takes misreading the meaning of this specific measure to mistake this as a fuel quality. This gets to the size of battery required to offer a specific number of watt hours of energy. Lithium Ion batteries have revolutionized device design by the energy densities, Small Battery Sizes, available.
My Apple AirPods are ridiculously small because the battery that powers them is insanely small. But, my first pair died in two years because of cycle life. I loved them to death. So everything works but you have to break them to fix the battery. Suck!