Principle and Current Status of Hydrogen Storage Technology

Hydrogen storage technology, as a bridge from hydrogen production to utilization, refers to the storage of hydrogen in a stable form of energy. Considering that hydrogen is a flammable and explosive gas, hydrogen storage technology must also consider factors such as safety, economy, energy consumption and service life. Generally, it is divided into physical hydrogen storage, chemical hydrogen storage and other hydrogen storage according to the principle of hydrogen storage.

1. Physical hydrogen storage technology

Physical hydrogen storage technology is mainly divided into high-pressure gaseous hydrogen storage and low-temperature liquefied hydrogen storage. It refers to the technology of simply increasing the density of hydrogen by changing the hydrogen storage conditions to achieve hydrogen storage. This technology is a purely physical process, does not require a hydrogen storage medium, has a low cost, is easy to release hydrogen, and has a high hydrogen concentration.

• High-pressure gaseous hydrogen storage technology refers to compressing hydrogen under high pressure and storing it in a high-density gaseous form. It has the characteristics of low cost, low energy consumption, easy dehydrogenation, and wide working conditions. It is the most mature and most commonly used hydrogen storage technology. The mass density of hydrogen increases with the increase of pressure, and the pressure is limited by the material of the storage tank. At present, high-pressure hydrogen storage tanks mainly include metal storage tanks, metal-lined fiber-wound storage tanks and fully composite lightweight fiber-wound storage tanks.
• Low-temperature liquefied hydrogen storage technology uses the characteristics of hydrogen liquefaction under high pressure and low temperature conditions, and its volume density is 845 times that of gaseous state to achieve efficient hydrogen storage. Its transportation efficiency is much higher than that of gaseous hydrogen, but it needs to break through the contradiction between liquid hydrogen insulation and hydrogen storage density during storage, bear the loss of about 1% caused by hydrogen gasification during hydrogen storage, and the loss of 30% of the mass energy of liquid hydrogen during insulation.

2. Chemical hydrogen storage technology

Chemical hydrogen storage technology mainly includes organic liquid hydrogen storage, liquid ammonia hydrogen storage, coordinated hydride hydrogen storage, inorganic hydrogen storage and methanol hydrogen storage. It is a technology that uses the hydrogen storage medium to react with hydrogen under certain conditions to form stable compounds, and then releases hydrogen by changing the conditions.

• Organic liquid hydrogen storage technology is based on the hydrogenation reaction of unsaturated liquid organic matter under the action of catalyst to generate stable compounds, and then dehydrogenation reaction is carried out when hydrogen is needed. However, it faces the disadvantages of high equipment cost, low hydrogen purity, and catalyst coking and deactivation under high temperature dehydrogenation conditions.
• Liquid ammonia hydrogen storage technology refers to the reaction of hydrogen and nitrogen to generate liquid ammonia, which is used as a carrier of hydrogen energy. The storage conditions of liquid ammonia are much milder than those of liquid hydrogen. The technical infrastructure of propane can be directly used, and the equipment investment is low. It is one of the most promising hydrogen storage technologies.
• Coordinated hydride hydrogen storage uses alkali metals to react with hydrogen to generate ionic hydrides, which decompose into hydrogen under certain conditions. As a promising hydrogen storage material, low-temperature hydrogen release performance technology, recovery, circulation, reuse and other technologies for this type of material need further research and development.
• Inorganic hydrogen storage materials are based on the mutual conversion between bicarbonate and formate to achieve hydrogen storage and release. This method is convenient for large-scale storage and transportation, and has good safety, but the hydrogen storage capacity and reversibility are not ideal.
• Methanol hydrogen storage technology refers to the reaction of carbon monoxide and hydrogen under certain conditions to generate liquid methanol, which is used as a carrier of hydrogen energy. Under certain conditions, methanol can be decomposed to obtain hydrogen for use in fuel cells. At the same time, methanol can also be used directly as fuel, and the storage conditions are normal temperature and pressure, and there is no irritating odor. Methanol hydrogen storage and liquid ammonia hydrogen storage are currently highly anticipated hydrogen storage technologies, with advantages such as reducing cost-end investment, achieving large-scale production, and reducing transportation risks.

3. Other hydrogen storage technologies

• Adsorption hydrogen storage is the use of adsorbents and hydrogen to achieve high-density hydrogen storage, mainly including materials metal alloys, carbonaceous materials, metal frames, etc. Metal alloy hydrogen storage refers to the use of hydrogen-absorbing metal A and metal B that does not absorb hydrogen or has a small amount of adsorption to make alloy crystals. Under certain conditions, metal A has a strong effect, hydrogen molecules are adsorbed into the crystal to form metal hydrides, and then by changing the conditions, the effect of metal A is weakened to achieve the release of hydrogen molecules. However, the disadvantage is that hydrogenation and dehydrogenation need to be carried out at high temperatures. Carbonaceous materials generally have a high mass density of hydrogen due to their large specific surface area and strong adsorption capacity. At the same time, carbonaceous materials also have the characteristics of light weight, easy dehydrogenation, strong anti-toxicity and high safety. At present, the internal material of 35~75MPa hydrogen storage bottles is mainly carbon fiber. Metal organic frameworks (MOFs), also known as metal organic coordination polymers, are zeolite-like materials with supramolecular microporous network structures formed by metal ions and organic ligands. The interaction between metals and hydrogen molecules can be enhanced by modifying organic components. It has the characteristics of large hydrogen storage capacity, high yield, adjustable structure and variable functions, but it needs to be operated under high temperature conditions. The future breakthrough space is how to improve the mass density of hydrogen under normal temperature and medium and high pressure conditions.
• Hydrate hydrogen storage technology refers to the storage of solid hydrates generated by hydrogen under low temperature and high pressure conditions. Since hydrates can be decomposed at room temperature and pressure, this method has a fast dehydrogenation speed and low energy consumption. At the same time, its storage medium is only water, which has the characteristics of low cost and high safety. The storage media include type II hydrate, type I hydrate, type H hydrate, and semi-cage hydrate, but due to their low hydrogen storage density, they do not meet practical requirements and need further research.

Hydrogen production by electrolysis of water is the most advantageous method for producing hydrogen. Utrasonic coating systems are ideal for spraying carbon-based catalyst inks onto electrolyte membranes used for hydrogen generation. This technology can improve the stability and conversion efficiency of the diaphragm in the electrolytic water hydrogen production device. Cheersonic has extensive expertise coating proton exchange membrane electrolyzers, creating uniform, effective coatings possible for electrolysis applications.

Cheersonic ultrasonic coating systems are used in a number of electrolysis coating applications. The high uniformity of catalyst layers and even dispersion of suspended particles results in very high efficiency electrolyzer coatings, either single or double sided.

About Cheersonic

Cheersonic is the leading developer and manufacturer of ultrasonic coating systems for applying precise, thin film coatings to protect, strengthen or smooth surfaces on parts and components for the microelectronics/electronics, alternative energy, medical and industrial markets, including specialized glass applications in construction and automotive.

Our coating solutions are environmentally-friendly, efficient and highly reliable, and enable dramatic reductions in overspray, savings in raw material, water and energy usage and provide improved process repeatability, transfer efficiency, high uniformity and reduced emissions.

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