A hybrid hydrolytic hydrogen storage system based on catalyst-coated hollow glass microspheres

Abstract

Summary Hydrogen‐pressurized hollow glass microspheres (HGMs) in combination with a hydride bear the potential of storing hydrogen in feasible amounts. Therefore, the approximately 20‐µm diameter spheres are heated up and pressurized with hydrogen at a pressure of 85 MPa, so hydrogen diffuses into the spheres. After the spheres are cooled down, hydrogen can be stored at room temperature without excessive security measures. To release the stored hydrogen, heat has to be applied again to reach temperatures of about 250 °C (523.15 K). To reach this temperature, it is suggested in this work to use an exothermal chemical reaction, which produces hydrogen as a by‐product. In this case, an NaBH4–water reaction will be discussed, which has to be initialized by a catalyst deployed on the HGMs. It will be shown that hydrogen storage densities of up to 20 wt% and 50 kg/m3 can be theoretically achieved with the proposed hydrogen storage system consisting of hydrogen‐pressurized HGMs and a hydride, that is, NaBH4. Volumetric storage density and other aspects, such as water management, temperature restriction, stoichiometric restriction and hydrogen diffusion through glass, will be discussed. Due to resulting high water vapour pressures, a pressure vessel will still be needed in the concept. This paper shall give an overview of theoretically achievable storage densities with the proposed system. Experiments were carried out regarding catalytic promoted hydrolysis with HGMs, and resulting storage densities were determined. These experiments show good agreement with theory. However, they will be addressed only briefly in the outlook of the paper because a detailed discussion would go beyond the scope of this work. Copyright © 2016 John Wiley & Sons, Ltd.

Glassy Microspheres for Energy Applications

“…Here it is where hollow glass microspheres can prove their capabilities: one can exploit the diffusion of hydrogen through the thin wall of an HGM at elevated temperatures and pressures, and then let the gas to be trapped upon cooling to room temperature. HGM with diameter in the range 1 to 100 μm, density between 1.0 and 2.0 gm/cc, and porous-wall structure with wall openings 1 to 100 nm represent a promising material for hydrogen storage, as demonstrated in recent papers and patents that have shown progress in the preparation and use of HGM for this application [ 95 , 96 , 97 , 98 , 99 ]. The storage of hydrogen at pressures up to 100MPa inside an HGM is possible due to the low diffusivity of hydrogen at room temperature; later, to release it, it is necessary to reheat the microspheres.…”

Enhanced Thermal Insulation of the Hollow Glass Microsphere/Glass Fiber Fabric Textile Composite Material

“…Therefore, the enhancement of its thermal insulation performance and the reduction in its overall density for lightweight in reducing energy consumption have become a key issue that needs to be resolved. Hollow glass microspheres (HGM), which are spherical and lightweight inorganic capsule, are widely used in some fields, such as coatings [ 18 ], plastics [ 19 ], aerospace [ 20 , 21 ], hydrogen storage [ 22 , 23 ], and building materials [ 24 ]. Having the advantages of isotropy, low density, good chemical stability, good moisture resistance, small and well-distributed internal stress, and low thermal conductivity, HGM have become a lightweight thermal insulation filler with a wide range of use and excellent performance [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ].…”

Low‐alkali borosilicate glass microspheres from waste cullet prepared by flame synthesis

“…These properties make them advantageous in aviation and the automotive industry, 34 and construction. [35][36][37] GM are also considered for hydrogen storage, 30,[38][39][40][41] energy-saving applications (thermal insulation), and also as luminescent or reflective materials. [42][43][44] Recently GM have proven to be versatile biomaterials.…”