Researchers from Soochow University in China report that the newly found B40—the first experimentally observed all-boron fullerene—when coated with 6 titanium atoms (Ti6B40) can store up to 34 hydrogen molecules, corresponding to a maximum gravimetric density of 8.7 wt%.
According to their DFT calculations, it takes 0.2-0.4 eV/H2 to add one H2 molecule—assuring reversible storage of H2 under ambient conditions. The evaluated reversible storage capacity was 6.1 wt%. An open access paper on their work is published in Nature’s Scientific Reports.
As an earth-abundant element, boron is widely applied for hydrogen storage with its chemical hydrides and nanostructural forms. Boron-based chemical hydrogen storage materials such as borohydrides (e.g., LiBH4 and NaBH4) are promising compounds because of their high hydrogen capacities. However, due to kinetic and/or thermodynamic limitations, the chemical hydrides suffer from poor reversibility, there are still difficulties in practical application of borohydrides. An efficient solution is to find suitable all-boron nanostructures as replacement.
Boron fullerenes are seen as efficient hydrogen storage media since they are light-weight and have the capability to bind with metal adatoms. … Recently, an all-boron fullerene-like cage cluster B40− was produced and observed. Its neutral counterpart B40 exhibits the fullerene-like cage (D2d symmetry) and is calculated to be the most stable structure among the B40 allotropes. The relevant theoretical simulation indicates that B40 fullerene is thermally stable at temperature as high as 1000K [727 ˚C]. This is the first experimental evidence for the existence of all-boron fullerene.
For the hydrogen storage materials, transition metal (TM) atoms are important components due to their strong attraction to hydrogen molecules. Among the TMs, titanium (Ti) is regarded as an ideal binding metal in nanomaterials since it takes great advantages in hydrogen storage.—Dong et al.
In their study, the researchers performed DFT calculations on the binding capability of different metal atoms (Ca and TM: Sc, Ti, V, Fe, Co, Ni, Cu) decorated B40 fullerenes. They also carried out simulations on hydrogen storage by metal-decorated B40 fullerenes.
Huilong Dong, Tingjun Hou, Shuit-Tong Lee & Youyong Li (2105) “New Ti-decorated B40 fullerene as a promising hydrogen storage material” Scientific Reports 5, Article number: 9952 doi: 10.1038/srep09952