Li-decorated B-doped biphenylene network for reversible hydrogen storage

Abstract

Hydrogen energy is the mainstream alternative to fossil fuels in the future. However, finding safe and efficient hydrogen storage materials has become a key obstacle to achieving a sustainable hydrogen economy. This paper proposes that exploring hydrogen storage property of synthesized biphenylene network (Fan et al., Science, 372:852-6 (2021)) is an effective way to overcome the obstacle. In this work, Li-decorated biphenylene networks with different proportions of B were systematically constructed. The structures, thermal stability, diffusion barriers, and hydrogen storage characteristics were explored. The electron-deficient B can significantly enhance the Li binding energy, and increase the diffusion energy barrier to prevent metal aggregation, which is better than N doping. The hydrogen adsorption energies are just within the ideal range to facilitate hydrogen desorption. When the pressure is 0.1 MPa, the critical temperature is 230–310 K. The hydrogen storage capacities of Li-decorated B-doped biphenylene network change from 6.30 wt% to 19.22 wt% with the increase of Li atomic concentration from 7.69 % to 25.00 %, exceeding the ultimate onboard hydrogen storage goal set by DOE. Considering the hydrogen storage density and metal polymerization, Li-decorated B-doped BPNs have excellent hydrogen storage properties compared with transition metal-decorated carbon material systems and alkali metal-decorated N-doped BPN systems. Therefore, Li-decorated B-doped BPNs are a kind of carbon material with great potential for hydrogen storage.