Hydrogen Storage and Pressure Increasing Ma31w203 吳俊儀

Hydrogen Storage Methods High Pressure Tanks Liquid Hydrogen Carbon Nanotube Surface Absorbtion MgH2 NaAlH4

Comparison of Methods Method % of Weight Hydrogen Volume 1kg Hydrogen Hydrogen Gas 200bar 100% 0.06 𝑚 3 Hydrogen Liquid 0.014 𝑚 3 Carbon Nanotube ~6-8% 0.2 𝑚 3 MgH2 7.6% 0.009 𝑚 3 NaAlH4 7.5%(5.6%) 0.01 𝑚 3

Where and How Hydrogen be Stored Hydrogen storage will be required onboard vehicles and at hydrogen production sites, hydrogen refueling stations, and stationary power sites. Possible approaches to storing hydrogen include: Physical storage of compressed hydrogen gas in high pressure tanks (up to 700 bar); Physical storage of cryogenic hydrogen (cooled to -253°C, at pressures of 6-350 bar) in insulated tanks; and Storage in advanced materials — within the structure or on the surface of certain materials, as well as in the form of chemical compounds that undergo a chemical reaction to release hydrogen.

Storage Background Compressed hydrogen dangerous; low energy density Liquefied hydrogen expensive; cooling and compressing results in loss of 30% of stored energy Metal hydrides deliver hydrogen safely at constant pressure; sensitive to impurities; store only up to 7 % of its weight Liquid carrier storage uses fossil fuels as source of hydrogen; defeats purpose of using alternative energy

Carbon Nanotubes Stable, lightweight, inexpensive Large active surface area Large internal volume if it can be accessed

Carbon Nanotubes Stores hydrogen in pores of microscopic tubes and within tube structures Similar storage mechanism as metal hydrides Capable of storing 4.2% to 65% of their own weight in hydrogen

Carbon Nanotubes Carbon Nanotubes Hydrogen storage in nanotubes