Lithium and sodium decorated PHE-graphene for high capacity hydrogen storage: A DFT and GCMC study

TL;DR

This study combines DFT and GCMC simulations to evaluate Li- and Na-modified PHE-graphene's potential for high-capacity hydrogen storage, demonstrating promising gravimetric densities and adsorption properties.

Contribution

It provides a detailed computational analysis of Li and Na decoration on PHE-graphene, revealing their effectiveness for hydrogen storage applications.

Findings

Maximum hydrogen gravimetric density of 15.20 wt% with Li decoration.

Li- and Na-modified PHE-graphene show high hydrogen adsorption capacity.

Adsorption enthalpy curves indicate favorable storage conditions.

Abstract

Porous nanocarbon materials are seen as potential excellent materials for hydrogen storage due to their high surface area, excellent cycling stability and favorable kinetics. This study employs Density Functional Theory (DFT) simulations to investigate key property of Li$^-$ and Na$^-$ modified PHE-graphene, including structural stability, electronic properties, and hydrogen storage capabilities. The results show that when each Li atom adsorbs six hydrogen molecules, the material reaches the maximum hydrogen adsorption gravimetric density of 15.20 wt%. Additionally, through Grand Canonical Monte Carlo (GCMC) simulations, we obtained the hydrogen weight ratios and adsorption enthalpy curves for Li- and Na-modified PHE under varying temperature and pressure conditions. These findings indicate that both Li- and Na-modified PHE-graphene are exceptional candidates for hydrogen storage materials, particularly in mobile applications.