Nanoconfined 2LiBH4eMgH2eTiCl3 in carbon aerogel scaffold for reversible hydrogen storage

Nanoconfinement of 2LiBH4–MgH2–TiCl3 in resorcinol–formaldehyde carbon aerogel scaffold (RF–CAS) for reversible hydrogen storage applications is proposed. RF–CAS is encapsulated with approximately 1.6 wt. % TiCl3 by solution impregnation technique, and it is further nanoconfined with bulk 2LiBH4–MgH2 via melt infiltration. Faster dehydrogenation kinetics is obtained after TiCl3 impregnation, for example, nanoconfined 2LiBH4–MgH2–TiCl3 requires ∼1 and 4.5 h, respectively, to release 95% of the total hydrogen content during the 1st and 2nd cycles, while nanoconfined 2LiBH4–MgH2 (∼2.5 and 7 h, respectively) and bulk material (∼23 and 22 h, respectively) take considerably longer. Moreover, 95–98.6% of the theoretical H2 storage capacity (3.6–3.75 wt. % H2) is reproduced after four hydrogen release and uptake cycles of the nanoconfined 2LiBH4–MgH2–TiCl3. The reversibility of this hydrogen storage material is confirmed by the formation of LiBH4 and MgH2 after rehydrogenation using FTIR and SR-PXD techniques, respectively.Fil: Gosalawit Utke, Rapee. Helmholtz-Zentrum Geesthacht; Alemania. Suranaree University of Technology; TailandiaFil: Milanese, Chiara. Università degli studi di Pavia; ItaliaFil: Javadian, Payam. University Aarhus; DinamarcaFil: Jepsen, Julian. Helmholtz-Zentrum Geesthacht; AlemaniaFil: Laipple, Daniel. Helmholtz-Zentrum Geesthacht; AlemaniaFil: Karmi, Fahim. Helmholtz-Zentrum Geesthacht; AlemaniaFil: Puszkiel, Julián Atilio. Helmholtz-Zentrum Geesthacht; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jensen, Torben R.. University Aarhus; DinamarcaFil: Marini, Amedeo. Università degli studi di Pavia; ItaliaFil: Klassen, Thomas. Helmholtz-Zentrum Geesthacht; AlemaniaFil: Dornheim, Martin. Helmholtz-Zentrum Geesthacht; Alemani

Hydrogen sorption in the LiH-LiF-MgB2 system

A composite material in the LiH-LiF-MgB2 system has been synthesized by high-energy ball milling. Some peaks in addition to that of the binary 2LiH-MgB2 and 2LiF-MgB2 systems are observed for the composite material by high-pressure differential scanning calorimetry (HP-DSC), indicating the formation of intermediate phases. In situ synchrotron radiation powder X-ray diffraction (SR-PXD) performed at 60 bar of H-2 and 390 degrees C shows a superposition of both reaction pathways that are typical for 2LiH-MgB2 and 2LiF-MgB2. After hydrogen absorption of the LiH-LiF-MgB2 composite the vibrational modes of LiBH4 were observed by attenuated total reflection infrared (ATR-IR) spectroscopy. The F-19 MAS NMR spectrum of the LiF-LiBH4 sample after heat treatment in hydrogen is strongly dominated by the centerband and spinning sidebands from LiF; in addition, a low-intensity resonance, very similar to that of [BF4](-) ion, is identified

Sorption behavior of the MgH2-Mg2FeH6 hydride storage system synthesized by mechanical milling followed by sintering

The hydrogen sorption behavior of the Mg2FeH6eMgH2hydride system is investigated via in-situ synchrotron and laboratory powder X-ray diffraction (SR-PXD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), particle size distribution (PSD) and volumetric techniques. The Mg2FeH6eMgH2 hydride system is obtained by mechanical milling in argon atmosphere followed by sintering at high temperature and hydrogen pressure. In-situ SR-PXD results show that upon hydriding MgH2 is a precursor for Mg2FeH6 formation and remained as hydrided phase in the obtained material. Diffusion constraints preclude the further formation of Mg2FeH6. Upon dehydriding, our results suggest that MgH2 and Mg2FeH6 decompose independently in a narrow temperature range between 275 and 300 C. Moreover, the decomposition behavior of both hydrides in the Mg2FeH6eMgH2 hydride mixture is influenced by each other via dual synergetic-destabilizing effects. The final hydriding/dehydriding products and therefore the kinetic behavior of the Mg2FeH6eMgH2 hydride system exhibits a strong dependence on the temperature and pressure conditions.Fil: Puszkiel, Julián Atilio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Gennari, Fabiana Cristina. Comision Nacional de Energia Atomica. Gerencia de Area de Aplicaciones de la Tecnologia Nuclear. Gerencia de Investigacion Aplicada; . Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Arneodo Larochette, Pierre Paul. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energia Atomica. Gerencia de Area de Aplicaciones de la Tecnologia Nuclear. Gerencia de Investigacion Aplicada; . Universidad Nacional de Cuyo; ArgentinaFil: Karimi, Fahim. Materials Technology. Institute of Materials Research; AlemaniaFil: Pistidda, Claudio. Materials Technology. Institute of Materials Research; AlemaniaFil: Gosalawit Utke, Rapee. Materials Technology. Institute of Materials Research; Alemania. Suranaree University of Technology. Institute of Science, School of Chemistry; TailandiaFil: Jepsen, Julian. Materials Technology. Institute of Materials Research; AlemaniaFil: Jensen, Torben R.. University of Aarhu. Center for Energy Materials, iNANO and Department of Chemistry; DinamarcaFil: Gundlach, Carsten. Lund University. MAX-lab; SuizaFil: Bellosta von Colbe, José. Materials Technology. Institute of Materials Research; AlemaniaFil: Klassen, Thomas. Materials Technology. Institute of Materials Research; AlemaniaFil: Dornheim, Martin. Materials Technology. Institute of Materials Research; Alemani

A Reversible Nanoconfined Chemical Reaction

Hydrogen is recognized as a potential, extremely interesting energy carrier system, which can facilitate efficient utilization of unevenly distributed renewable energy. A major challenge in a future "hydrogen economy" is the development of a safe, compact, robust, and efficient means of hydrogen storage, in particular, for mobile applications. Here we report on a new concept for hydrogen storage using nanoconfined reversible chemical reactions. LiBH4 and MgH2 nanoparticles are embedded in a nanoporous carbon aerogel scaffold with pore size D-max similar to 21 nm and react during release of hydrogen and form MgB2. The hydrogen desorption kinetics is significantly improved compared to bulk conditions, and the nanoconfined system has a high degree of reversibility and stability and possibly also improved thermodynamic properties. This new scheme of nanoconfined chemistry may have a wide range of interesting applications in the future, for example, within the merging area of chemical storage of renewable energy

LiF-MgB2 System for Reversible Hydrogen Storage

LiF-MgB2 composites are proposed for reversible hydrogen storage. With respect to pure LiBH4, a significantly kinetic destabilization regarding hydrogenation and dehydrogenation is accomplished. The reversible hydrogen storage capacity is up to 6.4 wt %. The kinetic properties are improved significantly during cycling. The formations of the hydridofluoride phases (LiBa4-yFy and LiH1-xFx) are observed by in situ synchrotron X-ray diffraction (XRD) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Hydrogenation and dehydrogenation mechanisms are described on the basis of the formation and decomposition of the hydridofluoride phases, respectively

2LiBH4–MgH2–0.13TiCl4 confined in nanoporous structure of carbon aerogel scaffold for reversible hydrogen storage

The investigations based on kinetic improvement and reaction mechanisms during melt infiltration, dehydrogenation, and rehydrogenation of nanoconfined 2LiBH4-MgH2-0.13TiCl4 in carbon aerogel scaffold (CAS) are proposed. It is found that TiCl4 and LiBH4 are successfully nanoconfined in CAS, while MgH2 proceeds partially. In the same temperature (25-500ºC) and time (0?5 h at constant temperature) ranges nanoconfined 2LiBH4-MgH2-0.13TiCl4 dehydrogenates completely 99% of theoretical H2 storage capacity, while that of nanoconfined 2LiBH4?MgH2 is only 94%. Nanoconfined 2LiBH4-MgH2-0.13TiCl4 performs three-step dehydrogenation at 140, 240, and 380ºC. Onset (the first-step) dehydrogenation temperature (140ºC), significantly lower than those of nanoconfined sample of 2LiBH4-MgH2 and 2LiBH4-MgH2-TiCl3 (DT = 140 and 110ºC, respectively) is in agreement with the decomposition of eutectic LiBH4-Mg(BH4)2 and lithium?titanium borohydride. For the second and third steps (240 and 380ºC),decompositions of LiBH4 destabilized by LiCl solvation and MgH2 are accomplished, respectively. In conclusion, dehydrogenation products are B, Mg, LiH, and TiH. Reversibility of nanoconfined 2LiBH4-MgH2-0.13TiCl4 sample is confirmed by the recovery of LiBH4 after rehydrogenation together with the formation of [B12H12] derivatives. The superior kinetics during the 2nd, 3rd, and 4th cycles of nanoconfined2LiBH4-MgH2-0.13TiCl4 to the nanoconfined 2LiBH4-MgH2 can be due to the formations of Ti-MgH2 alloys (Mg0.25Ti0.75H2 and Mg6TiH2) during the 1st rehydrogenation.Fil: Gosalawit Utke, Rapee. Institute of Materials Research; Alemania. Suranaree University of Technology; TailandiaFil: Milanese, Chiara. University of Pavia; ItaliaFil: Javadian, Payam. University of Aarhus; DinamarcaFil: Girella, Alessandro. University of Pavia; ItaliaFil: Laipple, Daniel. Institute of Materials Research; AlemaniaFil: Puszkiel, Julián Atilio. Institute of Materials Research; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cattaneo, Alice S.. University of Aarhus; DinamarcaFil: Ferrara, Chiara. University of Aarhus; DinamarcaFil: Wittayakhun, Jatuporn. Suranaree University of Technology; TailandiaFil: Skibsted, Jørgen. University of Aarhus; DinamarcaFil: Jensen, Torben R.. University of Aarhus; DinamarcaFil: Marini, Amedeo. University of Pavia; ItaliaFil: Klassen, Thomas. Institute of Materials Research; AlemaniaFil: Dornheim, Martin. Institute of Materials Research; Alemani

Nanoconfined 2LiBH4 - MgH2 in nanoporous carbon aerogel scaffolds for reversible hydrogen storage

Nanoconfined 2 LiBH4 - MgH2 is prepared with and without catalyst (TiCl3) by direct melt infiltration of bulk 2 LiBH4 - MgH2 into an inert carbon aerogel scaffold material. Homogeneous dispersion of MgH2, LiBH4 and TiCl3 in the nanoporous structure of carbon scaffold is assured by several means, such as SEM-EDS via focus ion beam technique, in situ synchrotron radiation powder X-Ray diffraction, and N2 adsorption-desorption. The nanoconfined 2LiBH4-MgH2 system with and without catalyst release 100% hydrogen storage capacity within 100 and 200 min respectively, while the time for the bulk material is 30 h. A reversible 10.8 wt % H2 with respect to the metal hydride content over 4 hydrogen release and uptake cycles is preserved from both the nanoconfined systems

Nanoconfined 2LiBH(4)-MgH2 Prepared by Direct Melt Infiltration into Nanoporous Materials

Nanoconfined 2LiBH(4)-MgH2 is prepared by direct melt infiltration of bulk 2LiBH(4)-MgH2 into an inert nanoporous resorcinol-formaldehyde carbon aerogel scaffold material. Scanning electron microscopy (SEM) micrographs and energy dispersive X-ray spectroscopy (EDS) mapping reveal homogeneous dispersion of Mg (from MgH2) and B (from LiBH4) inside the carbon aerogel scaffold. Moreover, nanoconfinement of LiBH4 in the carbon aerogel scaffold is confirmed by differential scanning calorimetry (DSC). The hydrogen desorption kinetics of the nanoconfined 2LiBH(4)-MgH2 is significantly improved as compared to bulk 2LiBH(4)-MgH2. For instance, the nanoconfined 2LiBH(4)-MgH2 releases 90% of the total hydrogen storage capacity within 90 mm, whereas the bulk material releases only 34% (at T = 425 degrees C and p(H-2) = 3.4 bar). A reversible gravimetric hydrogen storage capacity of 10.8 wt % H-2, calculated with respect to the metal hydride content, is preserved over four hydrogen release and uptake cycles

Hydrogen storage in Mg-LiBH4 composites catalyzed by FeF3

Mge10 mol% LiBH4 composite plus small amounts of FeF3 is investigated in the present work. The presence of LiBH4 during the milling process noticeably modifies the size and morphology of the Mg agglomerates, leading to faster hydrogenation and reaching almost the theoretical hydrogen capacity owing to enhanced hydrogen diffusion mechanism. However, the dehydrogenation of the system at low temperatures (300 C) is still slow. Thus, FeF3 addition is proposed to improve the dehydrogenation kinetic behavior. From experimental results, it is found that the presence of FeF3 results in an additional size reduction of the Mg agglomerates between ~10 and ~100 mm and the formation of stable phases such as MgF2, LiF and FeB. The FeB species might have a catalytic effect upon the MgH2 decomposition. As a further result of the FeF3 addition, the Mge10 mol%LiBH4e5 mol% FeF3 material shows improved dehydrogenation properties: reduced dehydrogenation activation energy, faster hydrogen desorption rate and reversible hydrogen capacities of about 5 wt% at 275 C.Fil: Puszkiel, Julián Atilio. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Centre for Materials and Coastal Research; AlemaniaFil: Gennari, Fabiana Cristina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Arneodo Larochette, Pierre Paul. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Troiani, Horacio Esteban. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Karimi, Fahim. Centre for Materials and Coastal Research; AlemaniaFil: Pistidda, Claudio. Centre for Materials and Coastal Research; AlemaniaFil: Gosalawit e Utke, Rapee. Centre for Materials and Coastal Research; Alemania. Institute of Science, Suranaree University of Technology; TailandiaFil: Jepsen, Julian. Centre for Materials and Coastal Research; AlemaniaFil: Jensen, Torben R.. University of Aarhus; DinamarcaFil: Gundlach, Carsten. University of Aarhus; DinamarcaFil: Tolkiehn, Martin. HASYLAB at DES; AlemaniaFil: Bellosta von Colbe, José. Centre for Materials and Coastal Research; AlemaniaFil: Klassen, Thomas. Centre for Materials and Coastal Research; AlemaniaFil: Dornheim, Martin. Centre for Materials and Coastal Research; Alemani