• Mortazavi, Bohayra
• Lee, Hoonkyung
• Rabczuk, Timon
• Bae, Hyeonhu

Abstract

<p>The recent experimental synthesis of the two-dimensional (2D) boron-graphdiyne (BGDY) nanosheet has motivated us to investigate its structural, electronic, and energy storage properties. BGDY is a particularly attractive candidate for this purpose due to uniformly distributed pores which can bind the light-metal atoms. Our DFT calculations reveal that BGDY can accommodate multiple light-metal dopants (Li, Na, K, Ca) with significantly high binding energies. The stabilities of metal functionalized BGDY monolayers have been confirmed through ab initio molecular dynamics simulations. Furthermore, significant charge-transfer between the dopants and BGDY sheet renders the metal with a substantial positive charge, which is a prerequisite for adsorbing hydrogen (H₂) molecules with appropriate binding energies. This results in exceptionally high H₂storage capacities of 14.29, 11.11, 9.10 and 8.99 wt% for the Li, Na, K and Ca dopants, respectively. These H₂storage capacities are much higher than many 2D materials such as graphene, graphane, graphdiyne, graphyne, C₂N, silicene, and phosphorene. Average H₂adsorption energies for all the studied systems fall within an ideal window of 0.17–0.40 eV/H₂. We have also performed thermodynamic analysis to study the adsorption/desorption behavior of H₂, which confirms that desorption of the H₂molecules occurs at practical conditions of pressure and temperature.</p>

Topics

• impedance spectroscopy
• pore
• simulation
• molecular dynamics
• Hydrogen
• density functional theory
• Boron
• two-dimensional