The battery of the iPhone XS has a electric charge of 2,658 mAh (9,568 Coulomb) and works on 3.81 volts. So the electrical energy stored in the battery is
3.81 V x 9,568 C = 36,454 J
that means approximately 36 kJ (kilo Joule).
One Joule in everyday life represents the energy required to lift a small apple (with a mass of 100g) vertically through one meter or the kinetic energy released when that same apple falls one meter to the ground.
So your fully charged iPhone XS approximately offers the energy released when 36,000 apples fall one meter to the ground.
If you don’t like s falling to the ground take chocolate bars.
Thanks for reading.