Li-decorated BC3 nanopores: Promising materials for hydrogen storage

TL;DR

This study explores Li-decorated BC3 nanopores as promising materials for hydrogen storage, demonstrating they outperform some existing materials and meet DOE targets under realistic conditions using advanced computational modeling.

Contribution

The paper introduces a novel application of Li-decorated BC3 nanopores for hydrogen storage, with detailed theoretical analysis of their capacities under practical conditions.

Findings

Li-decorated BC3 nanopores have higher hydrogen storage capacities than graphene and borophene.

They meet DOE targets for volumetric and gravimetric capacities at moderate temperatures.

Rotational freedom of H2 molecules significantly influences storage capacity.

Abstract

In the quest of new absorbent for hydrogen storage, we investigate the capacities of slit pores formed by two BC3 sheets decorated with Li atoms. Their hydrogen storage capacities are determined using density-functional theory in conjunction with a quantum-thermodynamic model that allows to simulate real operating conditions, i.e., finite temperatures and different loading and depletion pressures applied to the adsorbent in the charge-delivery cycles. We show that the capacities of the adsorbed hydrogen phase of Li-decorated BC3 slit pores are larger than those reported recently for graphene and Li-decorated borophene slit pores. On the other hand, the usable volumetric and gravimetric capacities of Li-decorated BC3 slit pores can meet the targets stipulated by the U.S. Department of Energy (DOE) for onboard hydrogen storage at moderate temperatures and loading pressures well below those used in the tanks employed in current technology. In particular, the usable volumetric capacity for pore widths of about 10 {\AA} meets the DOE target at a loading pressure of 6.6 MPa when depleting at ambient pressure. Our results highlight the important role played by the rotational degree of freedom of the H2 molecule in determining the confining potential within the slip pores and their hydrogen storage capacities.