Lithium-modified B3C2P3 monolayer as a promising medium for reversible hydrogen storage

Abstract

Although two-dimensional (2D) materials have been extensively studied as hydrogen storage media, the search for 2D materials with high hydrogen storage capacity and reversible hydrogen storage properties at room temperature remains challenging. In this context, B3C2P3 monolayer with Li modification is studied systematically by first-principles calculation. We find that Li-modified B3C2P3 monolayer can achieve a high hydrogen storage capacity of 8.99 wt% with an average adsorption energy of −0.23 eV/H2. Three of the H2 molecules are adsorbed around the Li atom, while the fourth H2 molecule is adsorbed above the buckled P atom due to the constricted space around the Li atom. Not only metal Li atoms but also the buckled substrate plays an important role in hydrogen adsorption, indicating that buckled 2D materials are more interesting and promising in hydrogen storage than flat 2D materials. The average desorption temperature (TD) calculated by van't Hoff formula is 293.84 K, which is very close to room temperature. In addition, at room temperature, the structure of hydrogen adsorption is stable at a low pressure of 3.21 MPa, suggesting a broad application prospect of in reversible hydrogen storage.