Novel synthesis of porous aluminium and its application in hydrogen storage

Abstract

A novel approach for confining LiBH4 within a porous aluminium scaffold was applied in order to enhance its hydrogen storage properties, relative to conventional techniques for confining complex hydrides. The porous aluminium scaffold was fabricated by sintering NaAlH4, which was in the form of a dense pellet, under dynamic vacuum. The final product was a porous aluminium scaffold with the Na and H2 having been removed from the initial pellet. This technique contributed to achieving highly dispersed LiBH4 particles that were also destabilised by the presence of the aluminium scaffold. In this study, the effectiveness of this novel fabrication method of confined/destabilised LiBH4 was extensively investigated, which aimed to simultaneously improve the hydrogen release at lower temperature and the kinetics of the system. These properties were compared with the properties of other confined LiBH4 samples found in the literature. As-synthesised samples were characterised using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Nitrogen Adsorption measurements. The hydrogen storage capacity of all samples was analysed using temperature programmed desorption in order to provide a comprehensive survey of their hydrogen desorption properties. The porous aluminium scaffold has a wide pore size distribution with most of the porosity due to pores larger than 50 nm. Despite this the onset hydrogen desorption temperature (Tdes) of the LiBH4 infiltrated into the porous aluminiumscaffold was 200 °C lower than that of bulk LiBH4 and 100 °C lower than that of nanosized LiBH4. Partial cycling could be achieved below the melting point of LiBH4 but the kinetics of hydrogen release decreased with cycle number.

Tuning LiBH4 for Hydrogen Storage: Destabilization, Additive, and Nanoconfinement Approaches

“…Sofianos et al proposed a novel Al scaffold by sintering pressed NaAlH 4 [148]. Despite the large pore size and its broad distribution, very low onset temperature was observed (<100 • C), suggesting that the synergies between nanoconfinement and chemical enhancement were effective.…”

Hydrogen Storage with Aluminum Formate, ALF: Experimental, Computational, and Technoeconomic Studies

“…Materials proposed for on-board H 2 use, − including V-btdd and Ni 2 ( m -dobdc), are judged most significantly by their high H 2 storage densities as close to room temperature as possible. This contrasts with the requirements of long-duration H 2 storage materials, where H 2 storage density is not the most important factor, given that space is not limited as it would be in a vehicle.…”

Deposition of Thin Alumina Films Containing 3D Ordered Network of Nanopores on Porous Substrates

“…Nanoporous thin films are widely used for various applications such as energy conversion and storage [ 1 , 2 , 3 , 4 ], the selective separation of molecules [ 5 , 6 , 7 ] and filtration [ 8 , 9 , 10 ]. Commercially available nanoporous membranes generally exhibit broad size distributions and relatively large thickness.…”

“…Depending on the desired application, the fabrication of membranes with a very small size can be desirable. For instance, in hydrogen separation, the maximum pore size is between 0.3 nm and 0.4 nm [ 4 , 11 ], while for CO 2 separation, the pore sizes range from 0.3 nm to 1.3 nm [ 12 ]. In water desalination, the pore size has a key role in governing the movement of water through the membrane.…”