Hydrogen Storage By Michelle Delepine CH 407H

Several options Metal Hydride Tanks Compressed Hydrogen Liquid Hydrogen Chemically Stored Hydrogen Carbon Nanotubes Glass Microspheres

Metal Hydride Tanks Metallic alloy Absorb H and release later Room temp or heat

Metal Hydride Tanks ProsCons  Safe  Constant pressure  Purifies H  No escape potential  Life related to purity Impurities fill tank  Small relative capacity 1-2% of weight 5-7% in 250° C  s

Compressed H H is compressed into high-pressure tank Tank material: aluminum or carbon/graphite compounds Liners have reduced leakage

Compressed H ProsCons  High energy density  Simple design  Occupies a large space  Would have to be 3,ooo times larger to store as much energy as a gasoline tank  Compression ($)  Held at higher pressures for larger scales of use  High escape potential  Safety checks: Seals

Liquefied H Insulated Reinforced

Liquefied H ProsCons  Can hold more in less volume than can compressed H  More energy per mass than gasoline  Needs -253°C  Compression and cooling ($)  Energy net loss 30%  Large tank for insulation  Safety (Escape potential)  Depends on tank integrity and temperature

Chemically stored H Chemical reaction combines H into stable compound Release H with second reaction

Chemically Stored H ProsCons  Most abundant element  Found in numerous chemical compounds  Can use various compounds  Doesn’t need storage tank  Produced on demand  Ammonia cracking  Methanol cracking  Partial oxidation  H cannot be released  Can be bulky and heavy if stored

Carbon nanotubes Microscopic carbon tubes (2 nanometers dia) Store H on microscopic pores Similar to metal hydrides

Carbon nanotubes ProsCons  Store % of weight  Refuel after 5000 km  Cannot be placed in predetermined positions during manufacturing  Cannot control electrical properties

Glass microspheres Tiny hollow glass spheres Warming H gas Cooling locks H inside Warming releases H

Glass microspheres ProsCons  Can be very safe  Resist contamination  Can be stored at low pressure  Glass breakage

References makes glass permeable releases H Filled by immersing in high- pressure sources.com/hydrogen/storage.html 8/23/ elcells/pdfs/25106.pdf elcells/storage/compressed_gas.html