Investigation on the hydrogen storage properties of Li -decorated B3N based on the first-principles

Abstract

This research employs first-principles methods to investigate hydrogen storage in lithium-doped two-dimensional B₃N monolayers, which are made of atoms of boron and nitrogen. The researchers confirmed through structural optimizations that when Li atoms attach to the B₃N surface (forming Li@B₃N), the material remains stable at room temperature (300 K) without breaking bonds. Characterized by an average adsorption energy of −2.06 eV, every Li atom adheres firmly to the surface, thereby inhibiting clustering among Li atoms. Charge analysis reveals that Li transfers electrons to the B₃N layer, creating localized electric fields that enhance hydrogen molecule adsorption. PDOS further proves this point, due to significant atomic orbital hybridization among the B (2p), N (2p), and Li (2p) states, resulting directly from charge transfer from the Li atom to the substrate. Simulations of hydrogen adsorption reveal that each lithium atom can stably adsorb up to eight hydrogen molecules, with an average adsorption energy per H₂ molecule ranging from −0.134 eV to −0.167 eV, satisfying criteria for reversible storage. The material achieves a hydrogen storage capacity of 15.1 wt%, and hydrogen release occurs at practical temperatures (172 K ∼ 214 K) near ambient conditions. Molecular dynamics simulations confirmed that the structure of Li@B₃N adsorbed eight hydrogen molecules remained stable at 200 K. This research delivers theoretical direction for creating high-efficiency hydrogen storage materials through metal atom modification of boron nitride sheets, advancing clean energy solutions.