1. Explain the best methods of storing hydrogen (What is the best methods of hydrogen storage?) Student Number: 11780045 Name: Takahito Taira

2. What is the hydrogen? General properties

3. Attractions of hydrogen 1.Hydrogen has high efficiency of energy conversion. 2. If we use electrolysis biomass garbage etc......, hydrogen can be obtained without fossil fuels. 3. Hydrogen would burn without carbon emissions. It is the most important merit ×

4. Expectations and Applications Hydrogen is expected …... as clean energy as a possible future carrier of energy The most active field of study in hydrogen storage is...... battery Fuel-cell car Mobile power source

5. Problems of storing hydrogen The most important thing is...... How to store hydrogen gas safely It is very difficult problem! Hydrogen gas is very resposive Air Hydrogen gas (4%) Static electricity Explosion Hydrogen dissolves in many metals. Leakage Cracks …... Crac k

6. General methods of storing hydrogen 1. Liquid hydrogen Merits: It is useful for transportation Demerits: ● Energy is needed to cool it down to around 20.268K. ● Liquid hydrogen has less energy density by ● volume than hydrocarbon fuels. Large energy loss! 2. Compressed hydrogen Merits: Demerits: ● Compressed hydrogen gas has good energy ● density by weight. ● This method requires a large tank to ● store hydrogen. ● Compression step for hydrogen gas ● requires more energy. Large energy loss!

7. The recent study of hydrogen storage 1. Metal hydrides Metal hydrides are the metals that absorb and release hydrogen. Merits: ● Metal hydrides can store ● hydrogen more than liquid ● hydrogen. ● Some metal hydrides have ● good energy dencity by ● volume. Metal hydride hydrogen storage Demerits: ● Most metal hydrides bind with hydrogen very ● strongly. High temperatures are required to release their hydrogen content. ● Some metal hydrides are very heavy. We can't install it in car as a battery. 2. Carbon nanotubes and Graphene Hydrogen carriers based on nanostructured carbon have been proposed. Carbon nanotubes Why? All the carbon atoms are on the surface It allow hydrogen easy access for bonding. Research has proven that graphene can store hydrogen efficiently. Graphene It was shown that not only can graphene store hydrogen easily, it can also release the hydrogen again. But...... This method requires to heat to high temperatures around 450 ℃.

8. Conclusio n There are various methods of storing hydrogen ● Liquid hydrogen ● Compressed hydrogen ● Metal hydrides ● Carbon nanotubes ● Graphene ● etc...... a better way to store hydrogen is metal hydrides. My conclusion is...... What is the best methods of storing hydrogen? a best method to store hydrogen is carbon nanotubes at the present time! Thank you for your attention!