You donot need the density of material to calculate the above asked different energy densities. Instead, If you know the total area and volume on which you have applied your active electrode material, then by applying the formula to calculate the different capacitance from galvanostatic charge discharge study as C= I.t/V.m for gravimetric capacitance in the unit F/g, For areal capacitance use formula as C= I.t/V.A in the unit F/cm^2 and for the volumetric capacitance, use C= I.t/V.v in the unit F/cm^3 Here, C is capacitance either gravimetric or areal or volumetric, I is applied current in GCD study, t is discharge time from GCD curve, V is potential or voltage limit in which you carry your study, m is active mass of electrode, A is area on which you applied your electrode material and v is volume on which you applied your material.

Now, when you have all the three types of capacitance, then by adjusting the units in the formula E= C V^2/2 to get the energy density with respect to any of your capacitance above calculated (gravimetric with unit of Wh/Kg, areal energy density with unit of Wh/cm^2 and volumetric energy density in the unit of Wh/cm^3.

Hope the above suggested process help you to calculate different types of energy densities!!

Thanks very much Sahil Thareja!! This helps a lot!

I would like to send this paper about your question.

There is a full guide to evaluate supercapacitors devices without misleading.

https://doi.org/10.1002/batt.202100093

If you require any further information, feel free to contact me