C=(nNAe)/3.6M

this is the formula for Energy storage capacity of Anode.

where

n is number of metal atoms adsorbed per mole of doped graphene [how this will be calculated]?

Na- Avogadro's Number

e = 1.6E-19

3.6 is the ratio for conversion of mAh to coulomb

M- Molar mass of doped graphene

paper reference Article Effects of heteroatom doping on the performance of graphene ...