Solid-State Hydrogen Storage Origin and Design Principles of Carbon-Based Light Metal Single-Atom Materials

Abstract

Solid-state storage of hydrogen molecules in carbon-based light metal single-atom materials is promising to achieve both high hydrogen storage capacity and uptake rate, but there is a lack of fundamental understanding and design principles to guide the rational design of the materials. Here, a theoretical relationship is established between the hydrogen capacity/rate and the structures of the heteroatom-doped-graphene-supported light metal Li single atom materials for high-efficient solid-state hydrogen storage, which is verified by combining spectroscopic characterization, H2 adsorption/desorption measurements, and density functional theory (DFT) calculations. Based on the DFT calculations, a novel descriptor Φ is developed to correlate the inherent properties of dopants with the hydrogen storage properties, and further to screen out the best dual-doped-graphene-supported light metal Li single-atom hydrogen storage materials. The dual-doped materials have a much higher hydrogen storage capability than the sole-doped ones and exceed the best carbon-based hydrogen storage materials so far.