ABSTRACT
Hydrogen energy is recognized for its renewability, cost-effectiveness, and environmentally friendly characteristics. These advantageous attributes position hydrogen energy as a viable solution for mitigating global warming concerns, particularly as a significant alternative to petroleum-based resources. Nevertheless, due to hydrogen's notably low energy density per unit volume (low volumetric density), its storage presents a considerable challenge, involving potential cost and difficulty. Therefore, it is crucial to devise efficient storage techniques that effectively address this challenge to expand the utilization of hydrogen as an energy carrier.
Nanomaterials have attracted significant attention due to their outstanding electronic, magnetic, optical, surface, and mechanical attributes. Their high surface area relative to volume facilitates improved interactions with hydrogen molecules, enabling efficient adsorption or absorption onto their surfaces—an advantageous feature for hydrogen storage applications. Notably, specific nanomaterials, such as carbon nanotubes and graphene, exhibit remarkable electronic conductivity, optimizing processes like hydrogen adsorption and desorption and improving overall storage performance.
In addition to their electronic properties, nanomaterials often demonstrate unique mechanical strengths and flexibility. This characteristic enables them to endure the stresses associated with hydrogen storage and release cycles, thereby contributing to the durability of the storage system. Furthermore, the tunable nature of nanomaterials allows for the engineering of specific pore sizes and structures. This tunability enhances the material's capacity to adsorb or store hydrogen, ultimately improving its overall storage performance.
Some nanomaterials also feature magnetic properties, presenting opportunities for the controlled release and retrieval of hydrogen. This additional layer of controllability enhances the precision of the storage process. Thus, leveraging these multifaceted properties, nanomaterials provide avenues for solid-state physical or chemical hydrogen storage, facilitating regenerable offboard storage and reversible onboard storage. Consequently, nanomaterials emerge as an appealing and efficient option for large-scale hydrogen storage solutions, offering a combination of enhanced properties and controllable storage processes.
Storing hydrogen in nanomaterials ensures compactness, lightness, reversibility, and safety in moderate conditions. Large amounts of hydrogen could potentially be stored in nanostructured systems like metal hydrides, carbon nanotubes, metal-organic frameworks, complex hydride/carbon nanocomposites, nanotubes, and nanoporous materials. This chapter centers on the economic and technical challenges of employing nanomaterials for hydrogen storage. It also offers an overview of advanced techniques and computational methods for characterizing nanomaterials to enhance hydrogen storage efficiency.
