# Route to Achieving Enhanced Quantum Capacitance in Functionalized Graphene based Supercapacitor Electrodes

## TL;DR

This study demonstrates that functionalizing graphene with specific ad-atoms like N, Cl, and P significantly enhances its quantum capacitance, which remains high across a range of temperatures, promising for supercapacitor applications.

## Contribution

The paper introduces a systematic DFT analysis showing how controlled doping with N, Cl, and P ad-atoms enhances quantum capacitance in graphene, a novel approach for supercapacitor electrodes.

## Key findings

- Quantum capacitance is significantly increased by doping with N, Cl, and P ad-atoms.
- Localized density of states near Fermi energy explains the capacitance enhancement.
- High quantum capacitance persists over a wide temperature range near room temperature.

## Abstract

We have investigated the quantum capacitance ($C_Q$) in functionalized graphene, modified with ad-atoms from different groups in the periodic table. Changes in the electronic band structure of graphene upon functionalization and subsequently the quantum capacitance ($C_Q$) of the modified graphene were systematically analyzed using density functional theory(DFT) calculations. We observed that the quantum capacitance can be enhanced significantly by means of controlled doping of N, Cl and P ad-atoms in the pristine graphene surface. These ad-atoms are behaving as magnetic impurities in the system, generates a localized density of states near the Fermi energy, which intern increases charge(electron/hole) carrier density in the system. As a result, a very high quantum capacitance was observed. Finally, the temperature dependent study of $C_Q$ for Cl and N functionalized graphene shows that the CQ remains very high in a wide range of temperature near the room temperature.