A review of progress and problems in hydrogen storage methods

Is hydrogen difficult to store? Hydrogen storage is one of the key challenges in realizing the full potential of hydrogen as a clean and sustainable energy carrier. There are several methods for hydrogen storage, each with its own advantages and limitations. In this review, we will discuss the progress and problems associated with the most promising hydrogen storage methods.

1. Compressed hydrogen gas storage: Compressed hydrogen gas storage is one of the most common hydrogen storage methods, where hydrogen is stored in high-pressure tanks. The key advantage of this method is its simplicity and reliability, as it does not require any complex or specialized equipment. However, compressed hydrogen gas storage has a low energy density, which makes it unsuitable for long-range transportation or large-scale energy storage applications. Additionally, the high-pressure tanks required for this method can be heavy and expensive, making it less practical for some applications.
2. Liquid hydrogen storage: Liquid hydrogen storage involves cooling hydrogen to extremely low temperatures (-253°C) to liquefy it and store it in insulated tanks. This method has a higher energy density than compressed gas storage, making it more suitable for long-range transportation and space applications. However, the low boiling point of liquid hydrogen makes it difficult to store and handle, and it requires specialized and expensive equipment.
3. Metal hydride storage: Metal hydrides are solid materials that can absorb and release hydrogen gas through chemical reactions. This method has a high energy density and can store hydrogen at lower pressures, making it a promising alternative to compressed gas storage. However, metal hydrides have limited hydrogen storage capacity and can be expensive to produce.
4. Carbon nanotube storage: Carbon nanotubes are tiny, hollow carbon fibers that can store hydrogen through physisorption. This method has the potential to achieve high hydrogen storage capacity and can store hydrogen at lower pressures than compressed gas storage. However, the cost of producing carbon nanotubes is currently high, and there are challenges associated with controlling the adsorption and desorption of hydrogen in carbon nanotubes.
5. Chemical hydrogen storage: Chemical hydrogen storage involves the use of chemical reactions to store hydrogen in a stable form and release it when needed. This method has the potential to achieve high hydrogen storage capacity and can store hydrogen at ambient conditions. However, chemical hydrogen storage requires complex chemical reactions and specialized equipment, which can be expensive and challenging to scale up.

In conclusion, hydrogen storage remains a critical challenge for the widespread deployment of hydrogen as a clean and sustainable energy carrier. While progress has been made in developing various hydrogen storage methods, each method has its own advantages and limitations. To overcome the challenges associated with hydrogen storage, continued research and development are required to improve the efficiency, scalability, and cost-effectiveness of hydrogen storage technologies.