Solid state hydrogen storage in alanates and alanate-based compounds: A review

The safest way to store hydrogen is in solid form, physically entrapped in molecular form in highly porous materials, or chemically bound in atomic form in hydrides. Among the different families of these compounds, alkaline and alkaline earth metals alumino-hydrides (alanates) have been regarded as promising storing media and have been extensively studied since 1997, when Bogdanovic and Schwickardi reported that Ti-doped sodium alanate could be reversibly dehydrogenated under moderate conditions. In this review, the preparative methods; the crystal structure; the physico-chemical and hydrogen absorption-desorption properties of the alanates of Li, Na, K, Ca, Mg, Y, Eu, and Sr; and of some of the most interesting multi-cation alanates will be summarized and discussed. The most promising alanate-based reactive hydride composite (RHC) systems developed in the last few years will also be described and commented on concerning their hydrogen absorption and desorption performance

Recent progress and new perspectives on metal amide and imide systems for solid-state hydrogen storage

Hydrogen storage in the solid state represents one of the most attractive and challenging ways to supply hydrogen to a proton exchange membrane (PEM) fuel cell. Although in the last 15 years a large variety of material systems have been identified as possible candidates for storing hydrogen, further efforts have to be made in the development of systems which meet the strict targets of the Fuel Cells and Hydrogen Joint Undertaking (FCH JU) and U.S. Department of Energy (DOE). Recent projections indicate that a system possessing: (i) an ideal enthalpy in the range of 20-50 kJ/mol H2, to use the heat produced by PEM fuel cell for providing the energy necessary for desorption; (ii) a gravimetric hydrogen density of 5 wt. % H2 and (iii) fast sorption kinetics below 110 °C is strongly recommended. Among the known hydrogen storage materials, amide and imide-based mixtures represent the most promising class of compounds for on-board applications; however, some barriers still have to be overcome before considering this class of material mature for real applications. In this review, the most relevant progresses made in the recent years as well as the kinetic and thermodynamic properties, experimentally measured for the most promising systems, are reported and properly discussed

Hydrogenation via a low energy mechanochemical approach: The MgB2 case

This work aims at investigating the effect that the energy transferred during particle collisions in a milling process entails on solid-gas reactions. For this purpose, the synthesis of Mg(BH4)2 from MgB2 in a pressurized hydrogen atmosphere was chosen as a model reaction. MgB2 was milled under a broad set of milling parameters (i.e. milling times and rotation regimes) and the obtained product thoroughly characterized. By proving the partial formation of Mg(BH4)2, the results of this investigation indicate that the energy transferred to the powder bed by the powder particles during milling is not negligible, in particular when the milling process is protracted for a long period

Dynamics of porous and amorphous magnesium borohydride to understand solid state Mg-ion-conductors

Rechargeable solid-state magnesium batteries are considered for high energy density storage and usage in mobile applications as well as to store energy from intermittent energy sources, triggering intense research for suitable electrode and electrolyte materials. Recently, magnesium borohydride, Mg(BH$_{4}$)$_{2}$, was found to be an effective precursor for solid-state Mg-ion conductors. During the mechanochemical synthesis of these Mg-ion conductors, amorphous Mg(BH$_{4}$)$_{2}$ is typically formed and it was postulated that this amorphous phase promotes the conductivity. Here, electrochemical impedance spectroscopy of as-received γ-Mg(BH$_{4}$)$_{2}$ and ball milled, amorphous Mg(BH$_{4}$)$_{2}$ confirmed that the conductivity of the latter is ~2 orders of magnitude higher than in as-received γ-Mg(BH$_{4}$)$_{2}$ at 353 K. Pair distribution function (PDF) analysis of the local structure shows striking similarities up to a length scale of 5.1 Å, suggesting similar conduction pathways in both the crystalline and amorphous sample. Up to 12.27 Å the PDF indicates that a 3D net of interpenetrating channels might still be present in the amorphous phase although less ordered compared to the as-received γ-phase. However, quasi elastic neutron scattering experiments (QENS) were used to study the rotational mobility of the [BH$_{4}$] units, revealing a much larger fraction of activated [BH$_{4}$] rotations in amorphous Mg(BH$_{4}$)$_{2}$. These findings suggest that the conduction process in amorphous Mg(BH$_{4}$)$_{2}$ is supported by stronger rotational mobility, which is proposed to be the so-called “paddle-wheel” mechanism

Application of a New Method for GWAS in a Related Case/Control Sample with Known Pedigree Structure: Identification of New Loci for Nephrolithiasis

In contrast to large GWA studies based on thousands of individuals and large meta-analyses combining GWAS results, we analyzed a small case/control sample for uric acid nephrolithiasis. Our cohort of closely related individuals is derived from a small, genetically isolated village in Sardinia, with well-characterized genealogical data linking the extant population up to the 16th century. It is expected that the number of risk alleles involved in complex disorders is smaller in isolated founder populations than in more diverse populations, and the power to detect association with complex traits may be increased when related, homogeneous affected individuals are selected, as they are more likely to be enriched with and share specific risk variants than are unrelated, affected individuals from the general population. When related individuals are included in an association study, correlations among relatives must be accurately taken into account to ensure validity of the results. A recently proposed association method uses an empirical genotypic covariance matrix estimated from genome-screen data to allow for additional population structure and cryptic relatedness that may not be captured by the genealogical data. We apply the method to our data, and we also investigate the properties of the method, as well as other association methods, in our highly inbred population, as previous applications were to outbred samples. The more promising regions identified in our initial study in the genetic isolate were then further investigated in an independent sample collected from the Italian population. Among the loci that showed association in this study, we observed evidence of a possible involvement of the region encompassing the gene LRRC16A, already associated to serum uric acid levels in a large meta-analysis of 14 GWAS, suggesting that this locus might lead a pathway for uric acid metabolism that may be involved in gout as well as in nephrolithiasis

NaAlH4 production from waste aluminum by reactive ball milling

Due to its thermodynamic properties and high reversibility, Ti doped sodium alanateis considered as a prototype hydrogen storage material. In this work we show how sodium alanate can be synthesized by reactive ball milling using aluminum particles obtained from recycled waste incineration slag. The synthesis was monitoredwith an in situ milling vial and characterized stepwise by PXD and DTA analyses. The sorption properties of the material were investigated using in situ synchrotron radiation PXD and volumetric analyses. A complete conversion of the starting reactants was obtained

A new potassium-based intermediate and its role in the desorption properties of the K–Mg–N–H system

In situSR-PXD experiments revealed a new reaction mechanism of amide–hydride anionic exchange for the K–Mg–N–H system

Extracorporeal CO 2 Removal During Renal Replacement Therapy to Allow Lung-Protective Ventilation in Patients With COVID-19-Associated Acute Respiratory Distress Syndrome

The aim of this retrospective multicenter observational study is to test the feasibility and safety of a combined extracorporeal CO 2 removal (ECCO 2 R) plus renal replacement therapy (RRT) system to use an ultraprotective ventilator setting while maintaining (1) an effective support of renal function and (2) values of pH within the physiologic limits in a cohort of coronavirus infectious disease 2019 (COVID-19) patients. Among COVID-19 patients admitted to the intensive care unit of 9 participating hospitals, 27 patients with acute respiratory distress syndrome (ARDS) and acute kidney injury (AKI) requiring invasive mechanical ventilation undergoing ECCO 2 R-plus-RRT treatment were included in the analysis. The treatment allowed to reduce V T from 6.0 ± 0.6 mL/kg at baseline to 4.8 ± 0.8, 4.6 ± 1.0, and 4.3 ± 0.3 mL/kg, driving pressure (ΔP) from 19.8 ± 2.5 cm H 2 O to 14.8 ± 3.6, 14.38 ± 4.1 and 10.2 ± 1.6 cm H 2 O after 24 hours, 48 hours, and at discontinuation of ECCO 2 R-plus-RRT (T3), respectively ( p < 0.001). PaCO 2 and pH remained stable. Plasma creatinine decreased over the study period from 3.30 ± 1.27 to 1.90 ± 1.30 and 1.27 ± 0.90 mg/dL after 24 and 48 hours of treatment, respectively ( p < 0.01). No patient-related events associated with the extracorporeal system were reported. These data show that in patients with COVID-19-induced ARDS and AKI, ECCO 2 R-plus-RRT is effective in allowing ultraprotective ventilator settings while maintaining an effective support of renal function and values of pH within physiologic limits

Hydrogen storage systems from waste Mg alloys

The production cost of materials for hydrogen storage is one of the major issues to be addressed in order to consider them suitable for large scale applications. In the last decades several authors reported on the hydrogen sorption properties of Mg and Mg-based systems. In this work magnesium industrial wastes of AZ91 alloy and Mg-10 wt.% Gd alloy are used for the production of hydrogen storage materials. The hydrogen sorption properties of the alloys were investigated by means of volumetric technique, in situ synchrotron radiation powder X-ray diffraction (SR-PXD) and calorimetric methods. The measured reversible hydrogen storage capacity for the alloys AZ91 and Mg-10 wt.% Gd are 4.2 and 5.8 wt.%, respectively. For the Mg-10 wt.% Gd alloy, the hydrogenated product was also successfully used as starting reactant for the synthesis of Mg(NH2)2 and as MgH2 substitute in the Reactive Hydride Composite (RHC) 2LiBH4 + MgH 2. The results of this work demonstrate the concrete possibility to use Mg alloy wastes for hydrogen storage purposes