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Mg(BH4)2 with several polymorphs, known as a high capacity (14.9 wt.%) hydrogen storage material, has become more intriguing due to the recently found new functions of gas physisorption and ionic conductivity. Here we review the state-of-the-art on the energy related functions of Mg(BH4)2. Mg(BH4)2 tends to form the stable intermediate [B12H12]2− when the dehydrogenation temperature is above 400 °C, the strong B-B bonding of which makes the rehydrogenation condition very harsh. In contrast, lower borane intermediate [B3H8]2− facilitates the rehydrogenation even at a mild condition of 100 °C, suggesting the possibility of reversible hydrogen storage in Mg(BH4)2. The porous polymorph γ-Mg(BH4)2 shows attractive gas adsorption properties in view of its unique hydridic surface and pore shape, and potentially can be applied in hydrogen adsorption and Kr/Xe selectivity. A new diffraction-based adsorption methodology was developed to characterize adsorption thermodynamics and kinetics of γ-Mg(BH4)2, providing a novel idea for the characterization of crystalline porous materials. Moreover, the potential of Mg(BH4)2 as an electrolyte is discussed in the last part. Mg(BH4)2·THF/DME acts as a liquid electrolyte in Mg-batteries, while anion substituted or neutral molecule derivatives of Mg(BH4)2 can act as solid-state electrolyte.

Magnesium and its alloys are the most investigated materials for solid-state hydrogen storage in the form of metal hydrides, but there are still unresolved problems with the kinetics and thermodynamics of hydrogenation and dehydrogenation of this group of materials. Severe plastic deformation (SPD) methods, such as equal-channel angular pressing (ECAP), high-pressure torsion (HPT), intensive rolling and fast forging, have been widely used to enhance the activation, air resistance, and hydrogenation/dehydrogenation kinetics of Mg-based hydrogen storage materials by introducing ultrafine/nanoscale grains and crystal lattice defects. These severely deformed materials, particularly in the presence of alloying additives or second-phase nanoparticles, can show not only fast hydrogen absorption/desorption kinetics but also good cycling stability. It was shown that some materials that are apparently inert to hydrogen can absorb hydrogen after SPD processing. Moreover, the SPD methods were effectively used for hydrogen binding-energy engineering and synthesizing new magnesium alloys with low thermodynamic stability for reversible low/room-temperature hydrogen storage, such as nanoglasses, high-entropy alloys, and metastable phases including the high-pressure {\gamma}-MgH2 polymorph. This article reviews recent advances in the development of Mg-based hydrogen storage materials by SPD processing and discusses their potential in future applications.

A highly complicated structure of Mg(en)1.2(BH4)2 was solved from single crystal synchrotron X-ray diffraction, the new Mg(en)2(BH4)2 was shown to be its decomposition intermediate. The role of less reactive amorphous Mg(BH4)2 was demonstrated.

In the electrochemical process, Pt nanoparticles (NPs) in Pt-based catalysts usually agglomerate due to Oswald ripening or lack of restraint, ultimately resulting in reduction of the active sites and catalytic efficiency. How to uniformly disperse and firmly fix Pt NPs on carbon matrix with suitable particle size for catalysis is still a big challenge. Herein, to prevent the agglomeration and shedding of Pt NPs, Ni species is introduced and are evenly dispersed in the surface of carbon matrix in the form of Ni-N-C active sites (Ni ZIF-NC). The Ni sites can be used to anchor Pt NPs, and then effectively limit the further growth and agglomeration of Pt NPs during the reaction process. Compared with commercial Pt/C catalyst, Pt@Ni ZIF-NC, with ultralow Pt loading (7 wt%) and ideal particle size (2.3 nm), not only increases the active center, but also promotes the catalysis kinetics, greatly improving the ORR and HER catalytic activity. Under acidic conditions, its half-wave potential (0.902 V) is superior to commercial Pt/C (0.861 V), and the mass activity (0.38 A per mg Pt) at 0.9 V is 4.7 times that of Pt/C (0.08 A per mg Pt). Besides, it also shows outstanding HER performance. At 20 and 30 mV, its mass activity is even 2 and 6 times that of Pt/C, respectively. Whether it is under ORR or HER conditions, it still shows excellent durability. These undoubtedly indicate the realization of dual-functional catalysts with low-Pt and high-efficiency properties.

Non-alcoholic fatty liver disease (NAFLD) is a major health problem in Western countries and has become the most common cause of chronic liver disease. Although NAFLD is closely associated with obesity, inflammation, and insulin resistance, its pathogenesis remains unclear. The disease begins with excessive accumulation of triglycerides in the liver, which in turn leads to liver cell damage, steatosis, inflammation, and so on. P38γ is one of the four isoforms of P38 mitogen-activated protein kinases (P38 MAPKs) that contributes to inflammation in different diseases. In this research, we investigated the role of P38γ in NAFLD. In vivo, a NAFLD model was established by feeding C57BL/6J mice with a methionine- and choline-deficient (MCD) diet and adeno-associated virus (AAV9-shRNA-P38γ) was injected into C57BL/6J mice by tail vein for knockdown P38γ. The results indicated that the expression level of P38γ was upregulated in MCD-fed mice. Furthermore, the downregulation of P38γ significantly attenuated liver injury and lipid accumulation in mice. In vitro, mouse hepatocytes AML-12 were treated with free fatty acid (FFA). We found that P38γ was obviously increased in FFA-treated AML-12 cells, whereas knockdown of P38γ significantly suppressed lipid accumulation in FFA-treated AML-12 cells. Furthermore, P38γ regulated the Janus Kinase-Signal transducers and activators of transcription (JAK-STAT) signaling pathway. Inhibition of P38γ can inhibit the JAK-STAT signaling pathway, thereby inhibiting lipid accumulation in FFA-treated AML-12 cells. In conclusion, our results suggest that targeting P38γ contributes to the suppression of lipid accumulation in fatty liver disease.

Among the factors which restrict the large-scale utilization of magnesium-based hydride as a hydrogen storage medium, the high operating temperature, slow kinetics, and air stability in particular are key obstacles. In this work, a novel method, namely hydriding combustion synthesis plus short-term mechanical milling followed by air exposure, was proposed to synthesize air stable and autocatalytic magnesium nickel hydride (Mg2NiH4), which shows excellent hydrogen absorption/desorption kinetics, capacity retention and oxidation resistance. The short-term-milled Mg2NiH4 can desorb 2.97 wt.% hydrogen within 500 s at 230 °C. Even after exposure under air atmosphere for 67 days, it can still desorb 2.88 wt.% hydrogen within 500 s at 230 °C. The experimental and theoretical results both indicated that the surface of as-milled Mg2NiH4 was easy to be oxidized under air atmosphere. However, the in-situ formed Ni during air exposure of Mg2NiH4 improved the hydrogen desorption kinetics, and the formed surface passivation layer maintained the hydrogen storage capacity and avoided further poisoning, which we called autocatalytic and self-protective effect. Such a novel dual effect modified the reaction activity and oxidation resistance of the air-exposed Mg2NiH4. Our findings provide useful insights into the design and preparation of air stable metal-based hydride for large-scale utilization and long-term storage.

Reversible hydrogen absorption/desorption, the very fundamental property of metal hydrides (MHs), can be utilized to innovate the water splitting process. Spontaneous hydrogen absorption by a MH electrode shifts the water reduction potential to 0.3 V above the reversible hydrogen electrode. Then, the absorbed hydrogen can be released to give H2 by thermal dehydrogenation at mild temperature below 70 °C by utilizing low grade heat. The MH mediated water splitting combines the electrochemical hydrogen absorption in Ni-MH batteries and the thermal dehydrogenation in gas phase hydrogen storage, which significantly reduces the electrical energy consumption for water splitting up to 25 kJ (mol H2)−1 compared to an ideal hydrogen evolution catalyst and also automatically leads to decoupled H2/O2 generation. The advantages and mechanisms of the MH mediated water splitting are demonstrated by MH electrodes with surface Pd coating.

The exploration of cheap and efficient electrodes for hydrogen evolution reactions (HER) is extremely challenging. Herein, we report a newly-designed V2O3@Ni hybrid grown in situ on nickel foam as an efficient HER catalyst. The nickel foam not only promoted the electron transfer rate as a supporting substrate, but also worked as the source of Ni to enhance the integration of catalyst components with abundant active sites. Moreover, benefitting from the synergistic effect of the interface between V2O3 and Ni, which accelerated the entire electrochemical kinetics and facilitated the electron transfer, the in situ V2O3@Ni hybrid catalysts afforded a small overpotential of 47 mV and 100 mV at a current density of 10 mA cm−2 in 1.0 M KOH and 1.0 M PBS, respectively, and with excellent long-term stability. In addition, this research provides a new route for the fabrication of noble-metal-free electrocatalysts with excellent HER performance over a broad range of pH values.

The hydrogen storage properties of the novel equiatomic TiZrNbFeNi and non-equiatomic Ti20Zr20Nb5Fe40Ni15 high entropy alloys (HEAs) were studied. These alloys were designed with the aid of thermodynamic calculations using the CALPHAD method due to their tendency to form single C14 Laves phase, a phase desirable for room-temperature hydrogen storage. The alloys, which were synthesized by arc melting, showed a dominant presence of C14 Laves phases with the (Zr, Ti)1(Fe, Ni, Nb, Ti)2 constitution and small amounts of cubic phases (

Objectives. To evaluate the role of short-term low-dose glucocorticoids in mild COVID-19 patients. Methods. We conducted a retrospective, cross-sectional, single-center study in Kunming, China. A total of 33 mild COVID-19 cases were divided into two treatment groups (with and without glucocorticoids, methylprednisolone, were used in this setting), and the absolute value of peripheral blood lymphocyte count; CD3+, CD4+, and CD8+ T cell counts; and the time to achieve negative transformation of a nucleic acid pharyngeal swab were recorded. Peripheral blood lymphocyte and T cell counts were compared between the treatment group and 25 healthy individuals. At the point of time when there was a 50% accumulation conversion rate (positive to negative nucleic acid on pharyngeal swab), and the nucleic acid turned negative in half of the patients in two groups, the peripheral blood lymphocyte and T cell counts were compared between treatment groups. Results. The mean cumulative time for the 50% negative conversion rate of the nucleic acid in the pharyngeal swab was 17.7±5.1 days and 13.9±5.4 days in the glucocorticoid group and the nonglucocorticoid group, respectively. The absolute peripheral blood lymphocyte count and the T cell subset count in the glucocorticoid group were lower than those in the nonglucocorticoid group. When the nucleic acid turned negative in half of the patients, the absolute value of peripheral blood lymphocyte count and CD4+ T cells of the glucocorticoid group and the nonglucocorticoid group was not significantly different; the CD3+ and CD8+ T cells in the glucocorticoid group were lower than those in the nonglucocorticoid group. The absolute peripheral blood lymphocyte count, CD3+ T cells, and CD4+ T cells in the glucocorticoid group were lower than those of the healthy group during the whole disease period, and CD8+ T cells returned to normal at 19-21 days of the disease period. There was no significant difference between the nonglucocorticoid group and the healthy group for absolute peripheral blood lymphocyte and CD8+ T cells; moreover, CD3+ T cells and CD4+ T cells were lower in the nonglucocorticoid group than those in the healthy group from the day of admission to the 18th day and returned to normal at the period of 19-21 days. The absolute peripheral lymphocyte count (P=0.048, effect size d=0.727) and T cell subset count (CD3: P=0.042, effect size d=0.655; CD4: P<0.01, effect size d=0.599; and CD8: P=0.034, effect size d=0.550) in the nonglucocorticoid group were higher than those in the glucocorticoid group, and the difference between the groups was statistically significant. Conclusions. This study found that the use of short-term, low-dose glucocorticoids does not negatively influence the clinical outcome, without affecting the final clearance of viral nucleic acid in mild COVID-19 patients.

Interactions between the active components with the support are one of the fundamentally factors in determining the catalytic performance of a catalyst. In contrast to the comprehensive understanding on the strong metal-support interactions (SMSI) in metal-based catalysts, it remains unclear for the interactions among different oxides in mixed oxide catalysts due to its complexity. In this study, we investigated the interaction between CeO2 and LaFeO3, the two important oxygen storage materials in catalysis area, by tuning the sizes of CeO2 particles and highlight a two-fold effect of the strong oxide-oxide interaction in determining the catalytic activity and selectivity for preferential CO oxidation in hydrogen feeds. It is found that the anchoring of ultra-fine CeO2 particles (

Lithium metal has been regarded as one of the most promising anode materials for high-energy-density batteries due to its extremely high theoretical gravimetric capacity of 3860 mAh·g−1 along with its low electrochemical potential of − 3.04 V. Unfortunately, uncontrollable Li dendrite growth and repetitive destruction/formation of the solid electrolyte interphase layer lead to poor safety and low Coulombic efficiencies (CEs) for long-term utilization, which largely restricts the practical applications of lithium metal anode. In this review, we comprehensively summarized important progresses achieved to date in suppressing Li dendrite growth. Strategies for protection of Li metal anodes include designing porous structured hosts, fabricating artificial solid electrolyte interface (SEI) layers, introducing electrolyte additives, using solid-state electrolytes and applying external fields. The protection of Li metal anodes can be achieved by regulating the stripping and deposition behaviours of Li ions. Finally, the challenges remaining for lithium metal battery systems and future perspectives for Li metal anodes in practical applications are outlined, which are expected to shed light on future research in this field.

Amorphous-nanocrystalline (a-nc) boron carbide thin films were prepared by chemical vapor deposition (CVD) by using ortho-carborane as a single-source precursor for inertial confinement fusion (ICF) application. The effects of deposition temperature (Tdep) and total pressure (Ptot) on chemical composition, microstructure, stoichiometry and morphology of the boron carbide films were investigated. The TEM results show that the structure of the film is mainly composed of amorphous boron carbide with dispersive nano-grains, which will be able to improve the mechanical properties of the film with relatively low roughness. The hardness of the (a-nc) boron carbide film obtained in this study reached 20.6 GPa, and roughness of 3.21 nm. The deposited films sized 0.2–1.9 μm in thickness with B/C atomic ratio ranged from 0.14 to 3.29. The deposition rate decreased with increasing deposition temperature and Ptot, while B/C ratio increased.

Despite potential of hydride-forming alloys for hydrogen storage, there have been few alloys which can reversibly store hydrogen without heating or activation treatment. In this study, a high-entropy alloy is designed for room temperature hydrogen storage based on three criteria: total valence electron concentration (VEC) of 6.4, single-phase thermodynamic stability (examined by CALPHAD calculations) and AB2H3 hydride formation (A: hydride-forming elements, B: elements without affinity to hydrogen, H: hydrogen). The designated alloy, TiZrCrMnFeNi containing 95 wt% C14 Laves phase, absorbs and desorbs 1.7 wt% of hydrogen (hydrogen-to-metal ratio: 1) at room temperature with a fast kinetics and without activation treatment.

The influences of Gd and Co co-substitution for La and Ni on phase structures, and electrochemical properties of La0.83-xGdxMg0.17Ni3.35-2xCo2xAl0.15 (x = 0-0.83) alloys were investigated. All the alloys contained A2B7-type (Ce2Ni7- and Gd2Co7-type) phase, Pr5Co19-type phase, PuNi3-type phase and CaCu5-type phase. The partial replacement of Gd and Co for La and Ni increased the phase abundance of the Ce2Ni7-type superstructure and decreased cell volumes, which contributed to a better hydrogen absorption capacity, cyclic stability and HRD. Compared to those of single Gd- or Co-substitutions, the synergistic effects of Gd and Co on the overall electrochemical properties of alloys were significant. Such a superior overall electrochemical performance may result from appropriate cell volumes and anti-pulverization abilities.

In order to satisfy the demand for the cyclic stability of commercial Ni-MH anodes, a PuNi3-type La0.6Gd0.2Mg0.2Ni2.6Co0.3Al0.1 alloy with excellent overall electrochemical properties was prepared by annealing the as-cast alloy sample at different temperatures for a week. The alloy had the highest PuNi3-type content of 86.9 wt% (1073 K), which offered a capacity retention of 69.6% after 100 cycles. However, 23.7 wt% PuNi3 type phase of the alloy constantly converted into the Ce2Ni7 type phase within a temperature increase of 50 °C, which improved the capacity retention by 12.1% under the same discharge capacity. We found that the addition of Gd did not change the stacked [LaMgNi4]/[LaNi5] superlattice and it maintained the structural stability of the crystal as well as its anti-corrosion, which is also a key factor to improve cyclic stability. These findings imply that alloys with both PuNi3-type and Ce2Ni7-type multiphase structures can be considered as a new choice for hydrogen storage.

Confinement of LiBH4 in porous materials is an efficient route to enhance the ionic conductivity of lithium, which seems to be associated with various types of scaffolding and its mixture ratios. In the present work, we reveal the effect of supports on ionic conductivity improvements based on a comparison of different silica supports, including micro-SiO2 (SM), porous nano-SiO2 (MSN), and nano-SiO2 with nanochannels (SBA-15). All LiBH4/silica composites exhibited higher lithium ionic conductivity, where LiBH4/SBA-15 (47% weight ratio) exhibited the highest conductivity of 3 × 10−5 S cm−1 at 35 °C, nearly three orders of magnitude higher than that of pure LiBH4. In addition, the LiBH4/SBA-15 composite has a wider electrochemical stability window of −0.2 to 5 V, satisfactory compatibility with the Li anode, and no occurrence of side reactions. These ionic conductivity enhancements can be attributed to the support effects of distinct SiO2, i.e., the increase in surface area for superior interfacial ionic conductivity and/or the increased disorder of LiBH4 for faster matrix ionic conductivity. The present study offers useful insights for designing a new hydride solid electrolyte for all-solid-state lithium ion batteries.

High-pressure torsion (HPT) is widely used not only as a severe plastic deformation (SPD) method to produce ultrafine-grained metals but also as a mechanical alloying technique to synthesize different alloys. In recent years, there have been several attempts to synthesize functional high-entropy alloys using the HPT method. In this paper, the application of HPT to synthesize high-entropy materials including metallic alloys, hydrides, oxides and oxynitrides for enhanced mechanical and hydrogen storage properties, photocatalytic hydrogen production and high light absorbance is reviewed.

Crystal structure and hydrogen storage properties of a novel equiatomic TiZrNbCrFe high-entropy alloy (HEA) were studied. The selected alloy, which had a A3B2-type configuration (A: elements forming hydride, B: elements with low chemical affinity with hydrogen) was designed to produce a hydride with a hydrogen-to-metal atomic ratio (H/M) higher than those for the AB2- and AB-type alloys. The phase stability of alloy was investigated through thermodynamic calculations by the CALPHAD method. The alloy after arc melting showed the dominant presence of a solid solution C14 Laves phase (98.4%) with a minor proportion of a disordered BCC phase (1.6%). Hydrogen storage properties investigated at different temperatures revealed that the alloy was able to reversibly absorb and fully desorb 1.9 wt% of hydrogen at 473 K. During the hydrogenation, the initial C14 and BCC crystal structures were fully converted into the C14 and FCC hydrides, respectively. The H/M value was 1.32 which is higher than the value of 1 reported for the AB2- and AB-type HEAs. The present results show that good hydrogen storage capacity and reversibility at moderate temperatures can be attained in HEAs with new configurations such as A3B2/A3B2H7.

Designing low-cost and highly efficient electrocatalysts has become a critical aspect to achieve sustainable energy production. Herein, we report the preparation strategy of MoS2 on Co-oxide nanoparticles embedded nitrogen-doped carbon nanosheets (Co-NC) those derived by ZIF-L anchored on a carbon cloth as an electrode for hydrogen evolution reaction (HER). The hybrid electrode denoted as MoS2/Co-NC/CC was synthesized in sequence of the growth of the leaf-like zeolitic imidazolate framework (Co-ZIF-L) on a carbon cloth (CC), the carbonization of the Co-ZIF-L and deposition of MoS2 by metal organic chemical deposition (MOCVD). The hierarchical porous catalyst presented remarkable electrochemical activity towards the HER in acidic solution, exhibiting great stability and fast kinetics with a small Tafel slope of 51 mV dec−1. Moreover, to produce a current density of 10 mA cm−2 (η10), MoS2/Co-NC/CC required a low overpotential of 111 mV, which is comparable with Pt.

Complex 3D microstructure and mechanical properties can be precisely characterized and linked by employing the X-ray micro-tomography combined with EBSD serial sectioning. Global sensitivity and principal component analysis can be used to rank and coarsen the contributing features that control the mechanical response. Afterwards, by creating surrogate models, the relationship between the most contributing features and mechanical properties can be further analyzed via support vector machines. The aforementioned novel approach was applied to study the relationship between 3D microstructural features and short crack behavior in a Ti-6Al-4V alloy. It was revealed that short crack path, growth rate, and its variation are mainly affected by the interaction with neighboring grains; however, as the short crack front becomes larger, there is a decrease and a change in the importance of those interactions. A high number of grains in contact with long cracked α grains in the loading direction may impose a constraint on the crack opening resulting in low crack growth rates. For the larger crack front, the increase in the shear stress field around the cracked grains leads to crack bifurcations and to the formation of secondary cracks, resulting in a decrease in crack driving forces with low crack growth rates. It was concluded that short crack behavior is strongly affected by the shape, size, and crystallographic features of its neighboring grains, which cause variation in the shear and tensile stress fields resulting in crack growth rate variation.

A nanosheet-like lithium borohydride hydrate (LiBH4·H2O) measuring 20–30 nm in thickness is successfully synthesized for the first time by a facile, scalable freeze-drying strategy. The prepared LiBH4·H2O nanosheets start releasing hydrogen below 50 °C and release an amount up to approximately 10 wt % at 70 °C because of the strong affinity of H+ in the H2O ligand and H– in the BH4 group. The reported dehydrogenation properties here are superior to those of all known complex hydrides, indicating applicability as an advanced chemical hydrogen storage medium.