High-pressure storage of hydrogen fuel: ammonia borane and its related compounds

As a promising candidate material for hydrogen storage, ammonia borane (NH3BH3) has attracted significant interest in recent years due to its remarkably high hydrogen content. Subjecting this material to high pressure not only enables the formation of novel phases and compounds with exotic properties, but also improves our basic understanding of material's behavior at different levels of atomic and molecular interactions. This review focuses on the perspective of high-pressure chemical hydrogen storage related to NH3BH3-based materials. Four main aspects are discussed: the structures and bonding of NH3BH3 over a wide pressure-temperature space, thermolysis of NH3BH3 at high pressure, the formation of a novel high-pressure H-rich compound as a result of storage of additional molecular H-2 in NH3BH3, and the potential rehydrogenation of the thermally decomposed NH3BH3 under the extreme of pressure.