Intermetallic compounds that can reversibly absorb, store and release a large amount of hydrogen at a certain temperature and hydrogen pressure.
According to the number of metal components of hydrogen storage alloys, they can be divided into binary system, ternary system and multivariate system. According to the main metal elements of hydrogen storage alloy materials, it can be divided into: rare earth system, magnesium system, titanium system, vanadium-based solid solution, zirconium system and so on. Metals constituting hydrogen storage alloys can be divided into hydrogen-absorbing type (denoted by A) and non-hydrogen-absorbing type (denoted by B). Accordingly, hydrogen storage alloys can be divided into AB5 type, AB2 type, AB type and A2B type.
2. Inorganic and organic hydrogen storage materials
Organic hydrogen storage technology began in 1980s. Hydrogen storage in organic matter is realized by a pair of reversible reactions between unsaturated liquid organic matter and hydrogen, namely catalytic hydrogenation and dehydrogenation. Hydrogen storage (chemical bonding) is realized by hydrogenation reaction, and hydrogen release is realized by dehydrogenation reaction.
3. Nano hydrogen storage materials
Nanomaterials have many unique physical and chemical properties because of their quantum size effect, small size effect and surface effect, and have become the frontier fields of physics, chemistry, materials and other disciplines. After nanocrystallization, many new thermodynamic and kinetic properties have appeared, such as obviously improved activation performance, higher hydrogen diffusion coefficient and excellent hydrogen absorption and desorption kinetic performance.
4. Carbon materials store hydrogen
Adsorption hydrogen storage has the advantages of safety, reliability and high storage efficiency. Among the materials for absorbing hydrogen storage, carbonaceous material is the best adsorbent, which is not only insensitive to a few gas impurities, but also can be reused. Carbon hydrogen storage materials are mainly activated carbon (AC), graphite nanofibers (GNF) and carbon nanotubes (CNT) with high specific surface area. ?
5, coordination hydride hydrogen storage
Hydrogen storage by coordination hydride is based on the properties of alkali metals (lithium, sodium, potassium, etc.). ) or alkaline earth metals (magnesium, calcium, etc. ) and the third main group element can form a coordination hydride with hydrogen. The main difference between metal hydride and metal hydride is that it is converted into ions or valence compounds during hydrogen absorption, while the hydrogen in metal hydride is stored in the alloy in atomic state.
6, hydrate hydrogen storage
Gas hydrate, also known as pore hydrate, is an ice-like crystal, which is composed of main holes formed by hydrogen bonds between water molecules and guest molecules under the action of weak van der Waals force.
Extended data
Hydrogen can be used as fuel and has the following characteristics:
superiority
1, rich in resources. It can be obtained by electrolysis with water as raw material. Water resources are relatively abundant, and oil and coal are the main fuels on the earth.
2. High calorific value. The calorific value of hydrogen combustion is the highest among all fuels. According to the measurement, the heat released by hydrogen combustion per kilogram is 1.4 * 10 8j, which is more than three times the calorific value of petroleum. Therefore, it has a small storage capacity, a large carrying capacity and a long journey.
Hydrogen is the cleanest fuel. The combustion product of hydrogen is water, which will not cause any pollution to the environment.
disadvantaged
It is not easy to store and transport hydrogen safely. It is light in weight, elusive, fast in diffusion, and needs low-temperature liquefaction, which will lead to valve blockage and unnecessary pressure.
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