A review: challenges, processes, and innovations in high-pressure hydrogen storage technologies

Hydrogen-powered vehicles are set to become a viable alternative for many of the cars currently on the roads. However, even if hydrogen offers a promising eco-friendly solution for the energy transition, several issues related to its storage and delivery need to be resolved in order to predict its wide use in both stationary and automotive applications. Hydrogen has the lowest volumetric energy density of all commonly used fuels (0.01079 MJ/L at atmospheric pressure). However, compression emerges as a direct and effective solution to this issue, with high pressures capable of significantly enhancing hydrogen's energy density, thereby augmenting its practicality. The energy densities achievable under high pressure are indeed impressive, making hydrogen highly practical. In mobile applications, hydrogen is typically stored as a gas in high-pressure composite overwrapped pressure vessels (COPVs). To achieve optimal functionality for high-pressure applications, two fundamental objectives must be met: ensuring exceptional structural integrity and maximizing gas impermeability. The commercialization of these vessels therefore presents a range of engineering challenges, including the development of advanced manufacturing techniques, the enhancement of structural properties, and the selection of appropriate materials, among others. The trend towards high-pressure hydrogen storage tanks is characterized by low cost, lightweight, and favorable safety performance. Consequently, the development of an efficient, sustainable, and safe high-pressure hydrogen storage method is a crucial focus of recent research, aiming to optimize hydrogen's utility in various applications. This review summarizes the latest developments in the most established hydrogen compression technologies.