Investigating the effect of cobalt loading on thermal conductivity and hydrogen storage capacity of hollow glass microspheres (HGMs)

Advancements in Solid-State Hydrogen Storage: A Review on the Glass Microspheres

“…The intriguing aspect of low thermal conductivity inherent in HGMs, a characteristic that contributes to their limited hydrogen release capacity, has sparked considerable interest among researchers. , A strategic approach to circumvent this limitation involves doping HGMs with transition metals or metal dopants. Elements such as magnesium and iron, cobalt, , and zinc have been employed to enhance the heat transfer characteristics of the microspheres, consequently amplifying their hydrogen storage capabilities. The research conducted by Dalai et al stands as a particularly emblematic example within this domain, focusing on the loading of transition metals.…”

“…Hollow glass microspheres (HGMs) have the characteristics of large voids, small size, and pressure resistance. They have commendable stability, − huge hydrogen storage capacity, cost-effectiveness, and resistance to hydrogen embrittlement. − These properties highlight the great potential of HGMs for hydrogen storage, providing a promising route to overcome the challenges inherent in current storage methods. Yet, research on refining HGMs for hydrogen storage is in its early stages, with a noticeable lack of inquiries into process conditions, material enhancements, and the basics of storage dynamics.…”

Recent Developments in Materials for Physical Hydrogen Storage: A Review

“…Overall, we summarize the general characterization of the glass microspheres in Table 3. Co-loaded HGMs have also been fabricated [59,60]. The results revealed that the number of pores in the HGMs increased significantly and that the hydrogen storage capacity reached a maximum of approximately 2 wt% at Co concentration ≤2 wt%.…”

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.…”

“…However, a limitation of HGM has been the poor thermal conductivity, which implies unsuitably low release rates of hydrogen gas; to overcome this problem, a proposed solution consisted of doping the glass with transition metals. As an example, cobalt loaded HGM, prepared by mixing cobalt nitrate hexahydrate with the glass powder and using an air-acetylene flame for melting the particles and producing the microspheres, showed an increase of thermal conductivity from 0.072 to 0.198 W/mK when the cobalt loading increased from 0 to 10 wt.% [ 97 ]. Hydrogen adsorption capacity, however, has a maximum for cobalt loading at 2 wt.%; beyond 2%, the storage capacity is said to decrease due to the closure of the pores by the uneven deposition of CoO on the surface of the microspheres [ 97 ].…”