Improved hydrogen storage in Ca-decorated boron heterofullerenes: a theoretical study

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 3; no. 15; pp. 771 - 7714
• Main Authors: Er, Süleyman, de Wijs, Gilles A, Brocks, Geert
• Format: Journal Article
• Language: English
• Published: 01.03.2015
• Subjects: Binding energy; Buckminsterfullerene; Calcium; Carbon; Density; Fullerenes; Hydrogen storage; Sustainability
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c4ta06818a

We computationally investigate the hydrogen storage properties of calcium-decorated C 48 B 12 boron-carbon heterofullerene molecules, and compare them to C 60 (all-carbon) fullerene decorated with calcium. We employ density functional theory (DFT) on the lowest energy configurations of C 48 B 12 molecules and find that these molecules have the following properties. (1) The most stable C 48 B 12 isomers have an electron affinity that is 0.93-1.04 eV higher than their carbon only counterpart. (2) The binding of a Ca atom to C 48 B 12 is ∼2.2 eV stronger than its binding to C 60 . (3) Unlike C 60 Ca x , x = 1-6, C 48 B 12 Ca x is stable with respect to decomposition into the fullerene molecules and Ca bulk metal. (4) C 48 B 12 Ca x binds up to six hydrogen molecules per metal center, leading to a gravimetric density of up to 7.1 weight percent (wt%). The hydrogen binding energies of up to ∼0.24 eV open a prospect of hydrogen storage at ambient temperature. Using first principles calculations we predicted new molecular based hydrogen storage systems, which are composed of abundant elements, with interesting thermodynamics.