Liu Han, Liu Chang, Li Quan, Ma Yanming, Chen Changfeng
State Key Laboratory of Superhard Materials and International Center for Computational Method and Software, College of Physics, Jilin University, Changchun 130012, China.
International Center of Future Science, Jilin University, Changchun 130012, China.
J Phys Chem Lett. 2021 Mar 4;12(8):2036-2043. doi: 10.1021/acs.jpclett.1c00109. Epub 2021 Feb 19.
Ammonia borane (NHBH) has long attracted considerable interest for its high hydrogen content and easy dehydrogenation conditions which make it a promising hydrogen storage material. Here, we report on a computational study of the structural stability and phase transition sequence of NHBH and associated lattice dynamics and electronic properties in a wide pressure range up to 300 GPa. The results confirm previously reported structures, including the experimentally observed orthorhombic 2 structure at low temperature and ambient pressure, and predict the phase transition sequence 2 → → 2 → 1̅ for NHBH. Our calculations also reveal systematic trends of monotonically decreasing band gap with rising pressure in the three high-pressure NHBH phases, which nevertheless all remain nonconducting up to the highest pressure of 300 GPa examined in this work. The present findings elucidate structural and electronic properties of NHBH over an extensive pressure range, providing knowledge essential to further study of NHBH in an expanded pressure-temperature phase space.
