Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
  • C01B3/0005—Reversible uptake of hydrogen by an appropriate medium, i.e. based on physical or chemical sorption phenomena or on reversible chemical reactions, e.g. for hydrogen storage purposes ; Reversible gettering of hydrogen; Reversible uptake of hydrogen by electrodes
  • C01B3/001—Reversible uptake of hydrogen by an appropriate medium, i.e. based on physical or chemical sorption phenomena or on reversible chemical reactions, e.g. for hydrogen storage purposes ; Reversible gettering of hydrogen; Reversible uptake of hydrogen by electrodes characterised by the uptaking medium; Treatment thereof
  • C01B3/0078—Composite solid storage mediums, i.e. coherent or loose mixtures of different solid constituents, chemically or structurally heterogeneous solid masses, coated solids or solids having a chemically modified surface region
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
  • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
  • B02C23/00—Auxiliary methods or auxiliary devices or accessories specially adapted for crushing or disintegrating not provided for in preceding groups or not specially adapted to apparatus covered by a single preceding group
  • B02C23/18—Adding fluid, other than for crushing or disintegrating by fluid energy
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/32—Hydrogen storage

Definitions

• the present invention relates to hydrogen-storing composite materials which are substantially reversibly convertible between a storage state and a non-storage state, and a process for producing the same.
• Hydrogen energy storage has become increasingly important in recent years.
• Today there are various techniques for storing hydrogen in which a distinction can be made between storage in gaseous, liquid or in the form of metal hydrides in a chemically bound state.
• the storage of gaseous or liquid hydrogen often leads to security problems.
• Hydrogen storage systems in which hydrogen is stored in the form of metal hydrides in chemically bonded state are therefore advantageous.
• Such metal hydride hydrogen storage devices have a storage state and a non-storage state, between which they can be converted substantially reversibly.
• NaAlH 4 alkali metal alkanoates NaAlH 4 , LiAlH 4 , Li 3 AlH 6 , LiNa 2 AlH 6 , CaAlH 5 and borohydrides such as LiBH 4 , NaBH 4 , Mg (BH 4 ) 2 , Ca (BH 4 ) 2 due to their relatively high mass-based hydrogen storage capacity.
• NaAlH 4 hydrogen is liberated, for example, in the following reaction steps:
• reaction step (I) the equilibrium temperature at 1 bar of hydrogen is 33 ° C., which corresponds to the measured reaction enthalpy of about 37 kJ / mol of H 2 , and for reaction step (II) HO 0 C, which corresponds to the measured reaction enthalpy of about 47 kJ / mol H 2 .
• reaction enthalpy changes when sodium is replaced by another alkali metal or an alkaline earth metal and / or aluminum by another element of the third main group of the periodic table of the elements.
• a hydrogen-storing composite material which is substantially reversible between a storage state and a non-storage state, and in the storage state, at least one complex metal hydride of alkali metal or alkaline earth metal and an element of the third main group of the Periodic Table of the Elements and at least one complex metal halide of alkali metal or alkaline earth metal and an element of the third main group of the Periodic Table of the Elements or in the storage state at least one complex metal halide of alkali metal or alkaline earth metal and an element of the third main group of the Periodic Table of the Elements and in the non-storage state at least one alkali metal or Alkaline earth metal halide and a metal of the third main group of the Periodic Table of the Elements contains.
• the halide is preferably selected from the group consisting of fluoride, chloride, bromide and mixtures thereof.
• the element of the third main group of the periodic table is preferably selected from the group consisting of boron, aluminum and mixtures thereof.
• the alkali metal is preferably selected from the group consisting of lithium, sodium, potassium and mixtures thereof.
• the alkaline earth metal is preferably selected from the group consisting of beryllium, magnesium, calcium and mixtures thereof.
• hydrogen-storing composite materials which, when loaded, comprise at least one complex metal hydride of lithium, sodium, magnesium and / or calcium, and aluminum or boron, and at least one complex metal halide of lithium, sodium, magnesium and / or calcium, and also aluminum or Boron containing, for example, composite materials containing Na 3 AlH 6 and Na 3 AlF 6 , Li 3 AlH 6 and Li 3 AlF 6 , NaAlH 4 and NaAlCl 4 , NaBH 4 and NaBF 4 , LiBH 4 and LiBF 4 , Ca (BH 4 ) 2 and Ca (BF 4 ) 2 , Ca (AlH 4 ) 2 and Ca (AlF 4 ) 2 , and / or Mg (BH 4 ) 2 and Mg (BF 4 ) 2 .
• thermodynamic reaction equilibrium of the transfer between a storage state and a non-storage state at a temperature of about -4o 0 C to 300 0 C, more preferably about -4o 0 C and 8O 0 C, in particular about 15 0 C to 4O 0 C, more preferably about 2O 0 C to 35 0 C and most preferably about 2O 0 C to 3O 0 C and a pressure of about 0.1 to 20 bar absolute, more preferably 1 to 10 bar absolute, even more preferably 5 to 8 bar absolute.
• Certain complex metal hydrides and / or complex metal halides of alkali metal or alkaline earth metal and an element of the third main group of the Periodic Table of the Elements have a perovskite structure.
• the composite materials according to the invention may contain further constituents, such as alkali metal or alkaline earth metal halides and / or metals of the third main group of the Periodic Table of the Elements and / or further complex hydrides.
• the reaction enthalpy of transfer between a storage state and a non-storage state is preferably 25 to 40 kJ / mol H 2 , preferably 25 to 35 kJ / mol, and more preferably about 30 kJ / mol H 2 .
• the hydrogen-storing composite materials according to the invention are preferably prepared by a process in which an alkali metal halide compound and / or an alkaline earth metal halide compound is mixed with a metal powder of an element of the third main group of the Periodic Table of the Elements and mechanically stressed, for example ground.
• a metal powder of an element of the third main group of the Periodic Table of the Elements and mechanically stressed for example ground.
• ball mills eg vibrating mills, attritors, etc.
• the milled mixture can then be hydrogenated.
• the molar ratio of alkali metal halide or alkaline earth metal halide to metal powder of an element of the third main group of the Periodic Table of the Elements is preferably 0.01: 1 to 100: 1, more preferably 0.1: 1 to 10: 1, and especially 0.5: 1 to 3: 1 and in particular about 1: 1.
• the grinding preferably takes place in an oxygen-poor and dry atmosphere, preferably ter a nitrogen atmosphere, an argon atmosphere, a hydrogen atmosphere, or under vacuum, more preferably at a pressure of 0.00001 mbar absolute to 10 bar absolute, preferably at a pressure of ambient pressure to 20 mbar above ambient pressure.
• the grinding preferably takes place at temperatures between 77 K and 115 0 C, preferably between 15 0 C and 35 0 C, more preferably 2O 0 C to 25 0 C instead.
• the hydrogenation is preferably carried out after introducing the alloy into a pressure vessel under conditions for which the pressure vessel is designed, preferably at a temperature between -4O 0 C and 300 0 C, more preferably between 15 0 C and 15O 0 C and a hydrogen pressure of 1 to 800 bar, preferably 5 to 100 bar, more preferably 10 to 50 bar.
• NaF and Al powders were mixed in a molar ratio of 1: 1 and ground for five hours in a planetary ball mill under inert gas (argon). Subsequently, the milled material was hydrogenated at 145 bar and 14O 0 C for eight hours. The hydrogenated material was dehydrated at 35O 0 C.
• Figure 1 shows an X-ray diffraction spectrum of the reaction product after five hours of grinding (upper spectrum), after hydrogenation at 14O 0 C and 145 bar (middle spectrum) and after the renewed dehydrogenation at 35O 0 C (lower spectrum).
• NaF and Al before the hydrogenation, NaF and Al are present as the only phase.
• the spectrum additionally shows a perovskite phase similar to Na 3 AlH 6 and Na 3 AlF 6 .
• After renewed dehydration again only NaF- and Al- Phases are detected.
• the material is thus substantially reversible between a memory state and a non-memory state can be transferred.
• FIG. 2 shows a spectrum of the sample after hydrogenation (upper spectrum) recorded by means of synchrotron diffractometry and the associated calculated bands (lower spectrum). This shows the presence of NaF, Al, Na 3 AlH 6 , Na 3 AlF 6 and NaAlH 4 phases.
• FIG. 3 shows the result of simultaneous TGA-DTA and MS measurements in the hydrogen region on hydrogenated material according to Example 1
• FIG. 4 shows the result of simultaneous TGA-DTA and MS measurements in the hydrogen region on pure NaAlH 4 .
• the TGA signal in Figure 3 shows that in the temperature range of 170-300 0 C, a mass loss occurs.
• the MS signal shows that this is hydrogen. Detection in the range of F 2 and HF showed no signs of release of fluorine atoms.
• FIG. 3 also shows that the reaction enthalpy for the decomposition of both phases NaAlH 4 and Na 3 AlH 6 is approximately the same.
• FIG. 5 shows the hydrogen uptake and release of NaH + NaF + 2 Al using the TiCl 4 catalyst measured by an Sievert's apparatus.
• FIG. 5 shows that reversible hydrogen absorption is possible.
• FIG. 6 shows the X-ray diffractometric measurement of the material after mixing and grinding, as well as after hydrogen absorption and renewed hydrogen desorption.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Combustion & Propulsion (AREA)
• Inorganic Chemistry (AREA)
• Food Science & Technology (AREA)
• Hydrogen, Water And Hydrids (AREA)
• Fuel Cell (AREA)

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• 2007
  • 2007-11-16 DE DE102007054843A patent/DE102007054843B4/de active Active
• 2008
  • 2008-10-30 WO PCT/EP2008/064721 patent/WO2009062850A1/de active Application Filing
  • 2008-10-30 CA CA2707987A patent/CA2707987A1/en not_active Abandoned
  • 2008-10-30 JP JP2010533533A patent/JP2011502938A/ja active Pending
  • 2008-10-30 EP EP08849758A patent/EP2215010A1/de not_active Withdrawn
  • 2008-10-30 CN CN200880124562XA patent/CN101910051A/zh active Pending
  • 2008-10-30 US US12/742,504 patent/US8926861B2/en active Active

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