Development of a solvent-free hydrogen storage and release system based on semi-solid-state ammonia borane (AB) fuel: high gravimetric capacity and feasibility for practical application

Abstract

Ammonia borane (AB), with high hydrogen contents and favorable dehydrogenation properties, is receiving intensive attention for its potential as a hydrogen storage material. In this study, we demonstrate a new type of solvent-free AB fuel system to obtain a high hydrogen systemic gravimetric capacity needed for practical fuel cell application. The new storage material constitutes AB soaked in tetraethylene glycol dimethyl ether (TEGDE) with catalytic amounts of palladium nanoparticles. Notably, TEGDE is very essential for the successful preparation of AB fuel system in a semi-solid state. The use of a minimum amount of TEGDE in this system allows the hybrid AB catalytic system to be fabricated as an efficient solvent and catalytic reaction medium, enabling a high gravimetric and volumetric capacity. For practical applications, AB pellets with spherical shapes have been manufactured by the co-precipitation of AB/TEGDE/PdNPs, followed by the compression of semi-solid AB fuel mixture for fuel transfer from the fuel tank to the hydrogen generator. Consequently, this hybrid semi-solid state catalytic system exhibits a high gravimetric capacity of hydrogen [10.01 material weight%]. With a high hydrogen capacity, a high performance dehydrogenation is obtained because of the synergistic effects facilitated by the highly active PdNPs well-dispersed in a TEGDE medium.