Energy Density is defined as the amount of energy stored in system or region of space per unit volume.
Energy Density = Energy / Volume.
Dimensional Formula of Energy = M1L2T-2
Dimensional Formula of Volume= M0L3T0
Putting these values in the given equation we get,
Dimensional Formula of Energy Density=M1L-1T-2
SI unit of Energy Density is J m-3 (Joule per cubic meter)