I wish to run DFT calculations on Quantum Espresso for the calculation of quantum capacitance. I have gone through literature, specifically, "Graphitic carbon nitride decorated with FeNi3 nanoparticles for flexible planar micro-supercapacitor with ultrahigh energy density and quantum storage capacity", wherein (in Figure 4e) they have, in short, mentioned calculation of quantum capacitance and have given equations.
I was wondering on how to go about this. Do I have to perform DOS or bandstructure before proceeding? Happy if anyone can help and guide on how and what Quantum Espresso calculations need to be carried out.