Hydrogen storage in sonicated carbon materials

Hirscher, Michael; Becher, M.; Haluška, M.; Dettlaff‐Weglikowska, Urszula; Quintel, Andrea; Duesberg, Georg S.; Choi, Yong‐Ki; Downes, Patrick; Hulman, Martin; Roth, S.; Stepanek, I.; Bernier, P.

doi:10.1007/s003390100816

Cited by 304 publications

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“…% hydrogen was stored in singlewalled nanotubes ͑SWNTs͒. However, controversial results 5,6 have been reported concerning the true hydrogen storage capacity on advanced carbons. Hirscher and his coworkers 5 argued against Dillon's report by showing that titanium hydrides in the SWNT stored large amounts of hydrogen, but the hydrogen storage capacity on SWNT itself was less than 1 wt.…”

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confidence: 99%

A candidate LiBH4 for hydrogen storage: Crystal structures and reaction mechanisms of intermediate phases

Kang

Kim

Han³

et al. 2005

Applied Physics Letters

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First-principles calculation and x-ray diffraction simulation methods have been used to explore crystal structures and reaction mechanisms of the intermediate phases involved in dehydriding of LiBH 4 . LiBH 4 was found to dehydride via two sequential steps: first dehydriding through LiBH, followed by the dehydriding of LiBH through LiB. The first step, which releases 13.1 wt. % hydrogen, was calculated to have an activation barrier of 2.33 eV per formula unit and was endothermic by 1.28 eV per formula unit, while the second step was endothermic by 0.23 eV per formula unit. On the other hand, if LiBH 4 and LiBH each donated one electron, possibly to the catalyst doped on their surfaces, it was found that the barrier for the first step was reduced to 1.50 eV. This implies that the development of the catalyst to induce charge migration from the bulk to the surface is essential to make LiBH 4 usable as a hydrogen storage material in a moderate temperature range, which is also important to stabilize the low-temperature structure of Pnma ͑no. 62͒ LiBH on dehydrogenation. Consequently, the high 13.1 wt. % hydrogen available from the dehydriding of LiBH 4 and LiBH and their phase stability on Pnma when specific catalysts were used suggest that LiBH 4 has good potential to be developed as the hydrogen storage medium capable of releasing the Department of Energy target of 6.5 wt. % for a hydrogen fuel cell car in a moderate temperature range. © 2005 American Institute of Physics. ͓DOI: 10.1063/1.2042632͔There is great interest in small and lightweight hydrogen storage materials. 1,2 Hydrogen fuel, which can be produced from renewable energy sources, contains a much larger chemical energy per mass ͑142 MJ kg −1 ͒ than any hydrocarbon fuel, thus making a hydrogen fuel cell an attractive alternative to the internal combustion engine for transportation. A hydrogen fuel cell car needs to store at least 4 kg hydrogen to cover the same range as a gasoline-powered car. 1 On the other hand, to store this hydrogen at room temperature and atmospheric pressure requires such a large volume that corresponds to a balloon with a 4.5 m diameter, which is hardly a practical volume for a small vehicle. To reduce this problem, one could consider using liquid hydrogen for hydrogen storage since it has a high mass density 1 ͑70.8 kg m −3 ͒. However, to liquefy hydrogen requires expensive processes due to its low condensation temperature 1 ͑−252°C at 1 bar͒. An additional problem is that heat transfer through the available modern containers can result in a loss of up to 40% of the energy content in hydrogen. 3 Currently, in this respect, there is much interest in storing hydrogen on advanced carbons and lightweight metals. Dillon et al. 4 reported that 6 -8 wt. % hydrogen was stored in singlewalled nanotubes ͑SWNTs͒. However, controversial results 5,6 have been reported concerning the true hydrogen storage capacity on advanced carbons. Hirscher and his coworkers 5 argued against Dillon's report by showing that titanium hydrides in the SWNT stor...

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confidence: 99%

A candidate LiBH4 for hydrogen storage: Crystal structures and reaction mechanisms of intermediate phases

Kang

Kim

Han³

et al. 2005

Applied Physics Letters

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“…This alloy, however, is also a hydrogen storage material. Hirscher et al (Hirscher et al, 2001) have shown that nearly all of the storage capacity of the sonicated samples examined in this work can be attributed to the hydrogen uptake of titanium alloy particles which have contaminated the carbon samples during sonication.…”

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confidence: 66%

Hydrogen Storage Using Carbon Nanotubes

Yao¹

2010

Carbon Nanotubes

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“…This result is consistent with many experiments, which reported that SWNTs have a certain hydrogen storage capacity at low temperature, [13][14][15] but have very low hydrogen uptake capacity at room temperature. [8][9][10][11][12] For H 2 molecules adsorbed on defected SWNTs, the situation is very different. Figure 7 shows a H 2 molecule stably adsorbed on the defected ͑10,10͒ SWNT at 300 K. Figure 7͑a͒ shows the radial distance of the adsorbed H 2 molecule from the adsorbing site on a defected ͑10,10͒ SWNT, versus annealing time at temperature, T = 300 K. It is obvious that this H 2 molecule is vibrating around its equilibrium distance without the trend of escaping from the tube in the time scale studied.…”

Section: B Adsorption Energies and Electron Density Contours Around mentioning

confidence: 99%

“…[5][6][7] In contrast to these reported promising results, other experimental measurements gave very discouraging results of hydrogen storage capacity in all examined carbon nanostructures, including SWNTs and MWNTs at room temperature. [8][9][10][11][12] Hydrogen storage in carbon nanotubes at low temperature and high pressure may be more suitable for obtaining higher hydrogen storage capacity. Hydrogen adsorption capacity more than 8 wt % in purified crystalline ropes of SWNTs was observed at ϳ128 atm and at 80 K. 13 A storage capacity of more than 6 wt % at T = 77 K and pressure 1 -2 atm for hydrogen physisorbed on heavily processed ropes of SWNTs was also reported.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of hydrogen physisorption on single-walled carbon nanotubes resulting from defects created by carbon bombardment

et al. 2005

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The defect effect on hydrogen adsorption on single-walled carbon nanotubes ͑SWNTs͒ has been studied by using extensive molecular dynamics simulations and density functional theory ͑DFT͒ calculations. It indicates that the defects created on the exterior wall of the SWNTs by bombarding the tube wall with carbon atoms and C 2 dimers at a collision energy of 20 eV can enhance the hydrogen adsorption potential of the SWNTs substantially. The average adsorption energy for a H 2 molecule adsorbed on the exterior wall of a defected ͑10,10͒ SWNT is ϳ150 meV, while that for a H 2 molecule adsorbed on the exterior wall of a perfect ͑10,10͒ SWNT is ϳ104 meV. The H 2 sticking coefficient is very sensitive to temperature, and has a maximum value around 70 to 90 K. The electron density contours, the local density of states, and the electron transfers obtained from the DFT calculations clearly indicate that the H 2 molecules are all physisorbed on the SWNTs. At temperatures above 200 K, most of the H 2 molecules adsorbed on the perfect SWNT are soon desorbed, but the H 2 molecules can still remain on the defected SWNTs at 300 K. The detailed processes of H 2 molecules adsorbing on and desorbing from the ͑10,10͒ SWNTs are demonstrated.

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Hydrogen storage in sonicated carbon materials

Cited by 304 publications

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A candidate LiBH4 for hydrogen storage: Crystal structures and reaction mechanisms of intermediate phases

A candidate LiBH4 for hydrogen storage: Crystal structures and reaction mechanisms of intermediate phases

Hydrogen Storage Using Carbon Nanotubes

Enhancement of hydrogen physisorption on single-walled carbon nanotubes resulting from defects created by carbon bombardment

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