Hydrogen storage properties on mechanically milled graphite

Ichikawa, Takayuki; Chen, D. M.; Isobe, Shigehito; Gomibuchi, Emi; Fujii, H.

doi:10.1016/j.mseb.2003.10.094

Cited by 49 publications

(53 citation statements)

References 7 publications

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“…Then, we studied H-storage properties of mechanically milled graphite under some hydrogen pressures up to 6 MPa in order to know whether the intrinsic H-storage properties of graphite are improved or not by increasing the milling hydrogen pressure up to 6 MPa. 66,67) In Fig. 11, the TDMS profiles of hydrogen are shown for mechanically milled graphite at a frequency of 10 Hz for 80 h under various H 2 -gas pressures by a vibrating ball mill equipment, together with that for graphite milled at 400 rpm for 80 h under a H 2 -gas pressure of 1 MPa by a planetary ball mill method as well.…”

Section: Hydrogen Storage Properties Of Graphite Based Materialsmentioning

confidence: 99%

“…On the other hand, the higher milling pressure gave suppression of the fracture rate of graphite structure more effectively, suggesting that the hydrogen atoms trapped at the edges of the graphene sheets and between the graphene sheets near the surface are responsible for preserving the lamellar structure of nanometer scale, which may be the host for H-storage on physisorption. 66,67) …”

Section: Appearance Of Physisorption-like Hydrogen Inmentioning

confidence: 99%

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Composite Materials based on Light Elements for Hydrogen Storage

et al. 2005

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In this paper, we review our recent experimental results on hydrogen storage properties of light elements Li, C and Mg based nanocomposite materials. The results are summarized as follows: In the Li-N-H system, such as the ball milled 1:1 mixture of Li amide and Li hydride containing a small amount of TiCl 3 (1 mol%), a large amount of hydrogen ($6 mass%) is absorbed and desorbed in the temperature range from 150 to 250 C with good reversibility and high reaction rate. Furthermore, in the ball milled mixture of 3Mg(NH 2 ) 2 and 8LiH, $7 mass% of hydrogen is reversibly stored in the temperature from 140 to 220 C, indicating one of the suitable hydrogen storage materials. In graphite containing a small amount of nanometer sized Fe ($2 at.%), a large amount of hydrogen ($7 mass%) is chemisorbed by ball milling for 80 h under less than 1 MPa of H 2 -gas pressure. However, the chemisorbed hydrogen capacity decreases with increase in the milling pressure for the 80 h ball milled graphite (down to $4:1 mass% at 6 MPa), while the physisorbed hydrogen capacity in graphite increases with increase in the milling pressure, reaching up to 0:5$1:0 mass% at 6 MPa. Unfortunately, the desorption temperature of chemisorbed hydrogen is higher than 300 C. Therefore, some break-through is necessary for the development of carbon-based materials as one of the hydrogen storage systems. On the other hand, some nano-composite Mg catalyzed by Ni nano-particle or Nb oxide reveals superior reversible hydrogen storage properties: $6:5 mass% of hydrogen is reversibly stored in the temperature range from 150 to 250 C. Especially, the Nb metals uniformly dispersed in nanometer scale on the surface of MgH 2 , which was produced by reduction of Nb 2 O 5 , is the best catalyst we have studied so far. Thus, it seems that some Mg nano-composites catalyzed by nano-particles of d-electron transition metals is acceptable for practical applications.

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Section: Hydrogen Storage Properties Of Graphite Based Materialsmentioning

confidence: 99%

Section: Appearance Of Physisorption-like Hydrogen Inmentioning

confidence: 99%

Composite Materials based on Light Elements for Hydrogen Storage

et al. 2005

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“…C nano H x is synthesized from graphite by the ball-milling under H 2 gas atmosphere. [13][14][15][16][17][18][19][20][21][22] So far, it has been reported that the hydrogenated nano-structural graphite (C nano H x ) can store about 7.4 mass% of hydrogen. 13 C nano H x material requires heating up to more than 700 C to release the hydrogen and desorbs hydrogen with hydrocarbons (CH 4 and C 2 H 6 ).…”

Section: Introductionmentioning

confidence: 99%

Microscopic characterization of metal-carbon-hydrogen composites (metal = Li, Mg)

Isobe

Yamada

Wang

et al. 2013

Journal of Applied Physics

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Li-C-H system, which can store about 5.0 mass% of rechargeable H 2 , has been reported as a promising hydrogen storage system by Ichikawa et al. [Appl. Phys. Lett. 86, 241914 (2005); Mater. Trans. 46, 1757Trans. 46, (2005]. This system was investigated from the thermodynamic and structural viewpoints. However, hydrogen absorption/desorption mechanism and the state of hydrogen atoms absorbed in the composite have not been clarified yet. In order to find new or better hydrogen storage system, graphite powder and nano-structural graphite ball-milled under H 2 and Ar atmosphere were prepared and milled with Li and Mg under Ar atmosphere in this study. Microstructural analysis for those samples by transmission electron microscope revealed that LiC 6 and/or LiC 12 were formed in Li-C-H system. On the other hand, MgC 2 was found in Mg-C-H system ball-milled under H 2 atmosphere, but not in the system ball-milled under Ar atmosphere. These results indicated that nano-structure in composites of nano-structural graphite is different from that of alkali (-earth) metal. For these reasons, metal-C-H system can be recognized to be a new family of hydrogen storage materials. V C 2013 AIP Publishing LLC.

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“…However, it has been experimentally confirmed that the maximum hydrogen concentration is 7 mass% in milled graphite. [12][13][14][15][16] This indicates that the amount of the hydrocarbon components in the thermally desorbed gases is abundant for nanostructural graphite milled by the rocking mill method because the hydrogen content does not depend on the milling method. From these results, it is concluded that the hydrogenated state in the nanostructural graphite is considerably affected by the milling conditions as well.…”

Section: Resultsmentioning

confidence: 99%

“…[12][13][14][15][16] However, higher temperature than 700 C is necessary to release all of the chemisorbed hydrogen from C nano H x , because the covalent bond between C and H is too strong to desorb hydrogen. 17) In this paper, we report on the issues how to destabilize the Li-H and C-H bonds.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Desorption Properties of Lithium–Carbon–Hydrogen System

2005

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Hydrogen desorption properties of a mixture of hydrogenated nanostructural graphite C nano H x and lithium hydride LiH are demonstrated in this paper, where C nano H x was synthesized from graphite by ballmilling under 1 MPa hydrogen for 80 h. First of all, we clarified the hydrogenated properties of C nano H x synthesized under four different milling conditions. The hydrogen desorption profile with typical two-peak structure was caused by iron contamination in C nano H x from steel balls during ballmilling, while the products prepared by zirconia balls showed the broad single peak in hydrogen desorption. The amount of desorbed hydrocarbon gas from the products using a rocking (vibrating) mill estimated by the thermogravimetry was larger than that using a rotating (planetary) one. Next, the destabilization properties of extremely stable LiH was examined, indicating that LiH was destabilized by mixing with another component LiOH or NaOH, and then, the mixture easily released hydrogen gas at lower temperature compared with LiH, LiOH and NaOH themselves. On the analogy of this result, we examined hydrogen desorption properties of the ballmilled mixture of LiH and C nano H x . The hydrogen desorption started from about 200 C and showed a peak at 350 C, although each product needs more than 400 C to release hydrogen. Since this hydrogen storage system is specially based on lithium, carbon and hydrogen in the mixture, it can be regarded as Li-C-H hydrogen storage system.

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Hydrogen storage properties on mechanically milled graphite

Cited by 49 publications

References 7 publications

Composite Materials based on Light Elements for Hydrogen Storage

Composite Materials based on Light Elements for Hydrogen Storage

Microscopic characterization of metal-carbon-hydrogen composites (metal = Li, Mg)

Hydrogen Desorption Properties of Lithium–Carbon–Hydrogen System

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Hydrogen storage properties on mechanically milled graphite

Cited by 49 publications

References 7 publications

Composite Materials based on Light Elements for Hydrogen Storage

Composite Materials based on Light Elements for Hydrogen Storage

Microscopic characterization of metal-carbon-hydrogen composites (metal = Li, Mg)

Hydrogen Desorption Properties of Lithium&ndash;Carbon&ndash;Hydrogen System

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Hydrogen Desorption Properties of Lithium–Carbon–Hydrogen System