Hydrogen Storage Applications Research Articles

Computational study of the mechanical stability, hydrogen storage and optoelectronic properties of new perovskite hydrides CsXH3 (X = Ca, Sr and Ba)

In this study, the physical properties of the perovskite hydrides CsXH3 (X = Ca, Sr and Ba) were explored using density functional theory (DFT) to assess their suitability for optoelectronic and hydrogen storage applications. The properties analyzed for these materials included hydrogen storage capacity, as well as structural, mechanical, electronic, and optical characteristics. These investigations were conducted using the GGA-PBE method within the ABINIT simulation code. Initially, the structural properties revealed that the lattice constants of the optimized unit cell structures of CsCaH3, CsSrH3 and CsBaH3 are 4.66, 4.80 and 5.25 Å, respectively. Additionally, the formation energy calculations proved that the selected materials are thermodynamically stable and can be synthesized. The mechanical stability of such hydrides has been confirmed by the results of the elastic constants that met the necessary stability criteria. Moreover, the hydrogen storage properties of the considered compounds revealed capacities of 1.71 wt%, 1.35 wt%, and 1.11 wt% for CsCaH3, CsSrH3 and CsBaH3, respectively, indicating their considerable potential as candidates for hydrogen storage applications. The electronic properties revealed that the three investigated materials exhibit semiconducting behavior with band gaps of 3.16, 2.84 and 2.18 eV for CsCaH3, CsSrH3 and CsBaH3, respectively. Additionally, various optical features including real ε1(ω) and imaginary ε2(ω) dielectric components, refractive index n(ω), absorption factor α(ω) were also investigated and implied that CsCaH3, CsSrH3 and CsBaH3 are suitable for optoelectronic devices. This study is the first to highlight the relevance of new materials CsCaH3, CsSrH3 and CsBaH3 for hydrogen storage and optoelectronic applications.

The structural, elastic, optoelectronic properties and hydrogen storage capability of lead-free hydrides XZrH3 (X: Mg/Ca/Sr/Ba) for hydrogen storage application: A DFT study

Perovskite hydrides are promising materials for hydrogen capacity application to achieve the US DOE on-board criteria. We have investigated novel perovskite hydrides XZrH3 (X: Mg/Ca/Sr/Ba) for H2 storage and transportation applications. In this study we investigates the physical properties of XZrH3 light materials for solid-state hydrogen storage application by incorporating the DFT framework with the CASTEP code. We have theoretically examined the structural, mechanical, electronic, optical, and hydrogen storage properties of these materials. The selected compounds were fully relaxed and optimized in the cubic phase space group Pm-3 m. Structural phase stability was confirmed through thermodynamic, and mechanical analyses. Mechanical properties, evaluated based on Poisson’s ratio, the Puagh’s ratio, and Cauchy pressure, indicate the ductile behavior with a preference for ionic bonding. The electronic structure analysis reveals the metallic behavior of these materials. Optical calculations were also performed to provide additional insights into the physical properties of H2 compounds. The gravimetric hydrogen storage capacities were calculated as 2.55, 2.25, 1.66, and 1.31 wt% for MgZrH3, CaZrH3, SrZrH3, And BaZrH3 hydrides respectively. The identified properties of XZrH3 suggest that these materials could significantly enhance hydrogen storage systems, with potential integration into existing energy technologies, offering a pathway toward more efficient and sustainable hydrogen-based solutions.

Effects of metals (X = Pd, Ag, Cd ) on structural, electronic, mechanical, thermoelectric and hydrogen storage properties of LiXH3 perovskites

Using the WIEN2K code, the hydrogen storage capabilities of lithium compositions like LiXH3 (X = Pd, Ag, Cd) hydrides are examined. Structural, electronic, mechanical, thermoelectric, and hydrogen storage properties of these hydrides are analyzed using first-principles simulations. Structural analysis of these compositions reveals that the hydrides are stable and belong to the cubic space group number (221 Pm-3 m). The thermodynamic stability of these hydrides are given in terms of formation energies and stability is checked through phonon dispersion curves. The purpose of the study is to calculate formation energy and breakdown temperature to determine stability of these hydrides. The metallic nature of all compositions are confirmed by band plots and density of states. The elastic properties are calculated to check the applicability of these compositions for applications involving hydrogen storage. The present paper represents the initial theoretical approach towards the future exploration of these materials for hydrogen storage applications.

Unlocking the potential of borophene nanoribbons for efficient hydrogen storage

This research explores the structural, electronic, optical, and hydrogen storage properties of borophene nanoribbons (BNRs) with armchair (ANR-B-H) and zigzag (ZNR B-H) edges. Computational simulations optimized these structures, revealing that 7ZNR-B-H has a superior binding energy. Chemical modifications, such as fluorine passivation and functionalization, influenced bond parameters and quantum properties. Bilayer BNRs showed increased stability and enhanced electrical conductivity. Our study demonstrated promising hydrogen storage capabilities, with passivated and functionalized BNRs achieving suitable adsorption energies and a significant gravimetric storage capacity of 20.32 wt%, exceeding DOE standards. NH2 functionalization notably improved adsorption energy, enhancing potential for efficient hydrogen storage. Changes in absorption spectra post-H2 adsorption further highlight BNRs’ potential for hydrogen storage applications. These findings provide valuable insights into BNRs, paving the way for their use in electronic devices and hydrogen storage systems.

Systematic study of first-row transition metals chlorides as reaction accelerators for Mg/ MgH2 for hydrogen storage application

Mg has been proposed as a possible hydrogen storage material. However, Mg necessarily requires the addition of a suitable material with catalytic activity to improve hydriding and dehydriding reactions. Some chlorides of transition metals have been tested as improvers of hydriding/dehydriding reactions in Mg/MgH2. However, experimental preparation and tested conditions are dissimilar among different published reports. A systematic study of first-row transition metal chlorides as additives is presented here to understand the various factors affecting the hydriding/dehydriding reactions in Mg/MgH2 prepared and tested under the same conditions. The added transition metal chlorides (TMClx, x = oxidation state) include metals in oxidation states +4, +3, and +2 whenever commercially available. Additional chlorides, such as ZrCl4 and AlCl3, were included for comparison. The mixtures of Mg-TMClx were produced employing cryogenic ball milled and characterized by i) temperature-programmed hydriding and dehydriding, ii) X-ray photoelectron spectroscopy at Mg, transition metals, and chlorine 2p edges, iii) X-ray diffraction, and iv) scanning electron microscope. The best additives are VCl3>TiCl4>NiCl2>AlCl3. In contrast, the worst additives among the first-row transition metal chlorides were CrCl2, ZnCl2, and CuCl2. They do not improve at all the hydrogen uptake kinetics of pure Mg. Chemical state, side reactions, crystal structure, and morphology were discussed as factors affecting the behavior of the hydriding and dehydriding reactions. A complex interrelationship among these factors is observed. However, the electronegativity of the transition metal and an interaction of the type Mg-TM-Cl, are proposed as the main factors for the observed improvement of hydriding and dehydriding reactions.

Advanced computational screening of X2CaH4 (X = Rb and Cs) for hydrogen storage applications

Utilizing cutting-edge computational screening methods, this study explores the hydrogen storage capacity of two complex metal hydrides, Cs2CaH4 and Rb2CaH4. We perform a thorough analysis of their structural, electrical, optical, and hydrogen storage properties using density functional theory (DFT). Within the I4/mmm space group, both compounds display stable tetragonal crystal structures, and their thermodynamic stability is confirmed by their formation energies. Notably, compared to Rb2CaH4, Cs2CaH4 is more stable. With band gaps of 2.99 eV for Cs2CaH4 and 3.28 eV for Rb2CaH4, the electronic properties show insulating behavior, which is beneficial for reducing electronic interference during hydrogen absorption and desorption. A comparative research reveals that the potential gravimetric hydrogen storage capacities of Cs2CaH4 (1.28%) and Rb2CaH4 (1.86%) are comparable to, albeit marginally less than, those of materials that are frequently explored, such as lithium borohydride. With their individual absorption and reflectivity peaks, the optical characteristics offer more information about how they interact with electromagnetic radiation, information that may be useful for improving their performance in real-world applications. Our results imply that Cs2CaH4and Rb2CaH4 have considerable potential for use in practical hydrogen storage systems, especially in situations where stability and minimal electronic interference are essential. Subsequent research endeavors may concentrate on enhancing the hydrogen storage capacity of these materials, so rendering their incorporation into existing hydrogen storage methods more feasible.

Agarose derived carbon based nanocomposite for hydrogen storage at near-ambient conditions

Nanocomposites of high surface area adsorption materials and nanosized transition metals have emerged as a promising strategy for hydrogen storage applications. However, their potential use in both transport and stationary applications depends on reaching the ultimate storage capacity at near-ambient conditions along with scalable synthesis protocols. Herein, a direct and simple thermal decomposition technique is reported to synthesize carbon-based nanocomposite, where nickel nanoparticles are dispersed in a porous carbon matrix. It is also demonstrated that the storage capacity can be enhanced at near-ambient conditions by effectively engineering the microstructure and synergistically combining the ‘physisorption’ and ‘spillover’ mechanism. The structure, composition and morphology of the samples were investigated using X-ray diffraction, energy dispersive spectroscopy, transmission and scanning electron microscopy. Sorption-desorption isotherms were obtained to study the hydrogen storage capacity at a moderate H2 pressure of 20 bar. The nanocomposite showed a promising storage capacity of 0.73 wt% at 298 K with reversible cyclability. It is shown that the uniform dispersion of catalytic nanoparticles leads to an increase in the spillover efficiency, which further helps in the enhancement of hydrogen storage capacity by a factor of 6.5 over pure carbon.

First-principle study on the structural, electronic and mechanical properties of High Entropy Alloy TiZrFeRu for hydrogen storage applications

High-entropy alloys are promising for hydrogen storage, especially in terms of their tunable hydrogen storage properties. Although several experimental studies, a fundamental and detailed atomistic comprehension of physical and electronic of the hydrogenation process is still lacking. This work investigated the structural, electronic and mechanical properties of TiZrFeRu high-entropy alloys (HEAs) using first-principle calculation. Indeed, we employed both density functional theory and density functional perturbation theory in the calculations with generalized gradient approximation and plane-waves pseudo-potential formalism. In addition, we used Virtual crystal approximation (VCA) to describe HEA as is well suited for predicting elastic properties. We have calculated relevant physical parameters, including lattice constants, elastic constants, elastic modulus, Poisson's ratio, Pugh's ratio, anisotropy factors and Vickers hardness..etc. Our calculated finding show that that TiZrFeRuH2 is mechanically stable and has a good ductility with a Pugh’s ratio (B/G) greater than 1.75. Lastly, we investigated and discussed electronic bandstructure, the total and partial electronic density of state. The results indicate that this compound exhibit a metallic character concentrated in a zone between -5 and 5 eV. The value of the Poisson ration (0.35) confirm again that this compound is metallic (for metal materials the Poisson ratio is above 0.25).

Evaluation and screening of multivariate metal-organic frameworks for hydrogen storage

Multivariate metal-organic frameworks (MTV-MOFs) are characterized by their unique structural feature of incorporating multiple organic linkers and metal ions into a unified framework. This composite construction bestows MTV-MOFs with a broader spectrum of diverse and intricate properties compared to traditional single-component MOFs. In this study, the performance of 560 MTV-MOFs as hydrogen storage adsorbents has been thoroughly investigated. Firstly, the key structural parameters of materials, including density, pore occupied accessible volume, accessible surface area, and porosity were computed. Then, high-throughput Grand Canonical Monte Carlo (GCMC) simulations were employed to calculate hydrogen adsorption capacity of MTV-MOFs under hydrogen pressures of 100 bar at both 77 K and 298 K. Based on simulated results, the deliverable hydrogen capacity of these MTV-MOFs were deduced under both room temperature conditions (298 K, 97.2 bar → 298 K, 5 bar) and low-temperature conditions (77 K, 100 bar → 160 K, 5 bar). Through high-throughput screening, we identified top ten promising MTV-MOFs with the highest hydrogen storage capacity and conducted in-depth studies on their hydrogen adsorption properties. Furthermore, we developed a multivariate linear regression model to quantitatively predict the relationship between hydrogen adsorption capacity and their structural parameters for these MTV-MOFs. The predictions of this model align closely with the outcomes derived from GCMC simulations. The present study highlights the potential of MTV-MOFs as promising candidates for hydrogen storage applications, thereby providing valuable theoretical insights into the exploration of high-capacity hydrogen storage materials.

Extensive screening of novel BaXH3 (X = V, Cr, Co, Ni, Cu, and Zn) perovskites for physical properties and hydrogen storage application: A DFT study

A successful transition to a sustainable economy depends on effective hydrogen storage. To achieve this, we investigate novel inorganic transition metal-based BaXH3 (X = V, Cr, Co, Ni, Cu, Zn) perovskites using Density Functional Theory (DFT). We compute key properties such as structural, electrical, magnetic, optical, mechanical, and hydrogen storage using the GGA-PBE functional. We calculate lattice constants and unit cell volume, indicate thermochemical stability with the negative formation energy of all compounds, and confirm thermodynamic stability with phonon calculations. Investigations into the band structure and density of states (DOS) show that all compounds are metallic, with BaVH3 and BaCrH3 exhibiting magnetic characteristics. We calculate the optical properties, including refractive index, dielectric function, reflectivity, loss function, conductivity, and absorption. We verified mechanical stability using the Born stability criteria. We calculated the hydrogen storage capacities and desorption temperatures. These results indicate that the studied compounds are potential candidates for hydrogen storage in a green economy.

Investigation on the hydrogen storage properties, electronic, elastic, and thermodynamic of Zintl Phase Hydrides XGaSiH (X = sr, ca, ba)

This study presents a comprehensive investigation of the electronic, mechanical, and thermodynamic properties of Zintl phase hydrides XGaSiH (X = Sr, Ca, Ba) using Density Functional Theory (DFT) and the FP-LAPW method within the WIEN2k package. Our analysis covers the structural stability, electronic properties, and hydrogen interaction mechanisms in these compounds. The hydrides exhibit narrow band gaps, with values ranging from 0.1 to 0.5 eV using GGA and LDA functionals, and 0.6–1.0 eV with mBJ-GGA and mBJ-LDA. The hydrogen storage capacities are determined to be 0.34 wt %, 0.47 wt %, and 0.40 wt % for SrGaSiH, CaGaSiH, and BaGaSiH, respectively, highlighting their potential for energy storage applications. Thermodynamic properties, evaluated through the quasi-harmonic Debye model, provide insights into the Grüneisen parameter, heat capacity, and thermal expansion coefficient over a range of pressures (0–50 GPa) and temperatures (up to 1000 K). Elastic constants reveal that these compounds are mechanically stable, with a notable anisotropy in the {100} plane and varying degrees of compressibility among the different hydrides. Our study further highlights the slightly ordered hexagonal Ga and Si layers, which contribute to the enhanced hydrogen storage capabilities of these materials. The compounds demonstrate high structural stability, facilitating effective hydrogen retention and release at practical temperatures, making them promising candidates for hydrogen storage applications. Additionally, the analysis of electronic band structures and density of states suggests significant conductivity potential, with band gaps ranging from 0.1 to 1.0 eV, depending on the computational method used. The unique combination of structural, electronic, thermodynamic, and mechanical properties in XGaSiH compounds positions them as valuable materials for renewable energy applications. These findings lay the groundwork for future research focused on optimizing these materials through structural modifications or doping to enhance performance metrics such as hydrogen storage capacity and electrical conductivity.

Synergistic Enhancements of Zn-ZIF with Nano Zinc Oxide for Hydrogen adsorption, energy storage, and photocatalytic technologies

Creating the porous Zinc-Zeolitic Imidazolate Framework (Zn-ZIF) using a solvothermal technique addresses the need for advanced materials with distinctive properties and cost-effectiveness in modern applications. The PXRD, SEM, UV-DRS, TEM, and TGA/DTG are used to characterize different concentrations of Zn-ZIF. Zn-ZIF's crystalline structure and phase purity have been verified by PXRD. Using diffuse reflectance spectra, the Kubelka-Monk function determined the band gaps of the Zn-ZIF samples, and scanning electron microscopy revealed a more porous structure. At 77 K and 1 bar, the Zn-ZIF solution with a 2:1 ratio had the highest hydrogen storage capacity (1.71 wt%). The electrochemical behavior of several Zn-ZIF electrodes in a 6 M KOH electrolyte was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) experiments. The Zn-ZIF electrode with a 2:1 ratio exhibits a low charge transfer resistance and a high proton diffusion coefficient (D) of 1.687 × 10−4 cm2 s−1. The characteristics of the 2:1 synthesized Zn-ZIF electrode as a supercapacitor were investigated. Our analysis of the generated Zn-ZIF material's specific capacitance values after 2000 cycles revealed an impressive retention rate of nearly 89 %, with values of 296.6 Fg-1. In addition, we examined the photocatalytic activities of the as-synthesized material by exposing it to ultraviolet light and seeing how it degraded organic dyes such as Cango-Red (CR) dye. With a photocatalytic efficacy of 95.06 % for CR dye, Zn-ZIF (2:1 ratio) is the most effective. These findings should provide new knowledge for researchers interested in developing novel Zn-ZIF materials for photocatalytic, energy storage, and hydrogen storage applications.

Enhance hydrogen storage in lightweight solid-state systems based on Poly(vinylnaphthalene)

This article highlights the potential of poly(2-vinylnaphthalene) (PVN) as a novel light-weight solid-state hydrogen storage system for various applications. With an impressive theoretical gravimetric hydrogen capacity of 5.2 wt.-%, PVN stands out for its attractiveness as a hydrogen carrier. The material possesses advantageous characteristics, including moldability, low toxicity, and ease of storage, making it a promising candidate for both stationary and mobile hydrogen storage applications. Experimental findings demonstrate that PVN can be hydrogenated by up to 76 % utilizing an Ru/Al2O3 catalyst at 250 °C for 24 h. Confirmation of the hydrogenation reaction, which results in poly(2-vinyldecalin), was achieved through characterization techniques such as FTIR, 1H NMR, and spectroscopic ellipsometry. The study of the effects of hydrogen pressure and reaction time identified moderate conditions as favorable, though a further exploration of different catalysts is suggested for optimal conversion. A palladium-based catalyst was employed to release hydrogen from the hydrogenated polymer, demonstrating almost complete reversibility of the hydrogenation of poly(2-vinylnaphthalene) with a dehydrogenation yield of 90 %.

Critical assessment of the validity of quasi-static pore network modeling in the application of underground hydrogen storage

This study explores the suitability of quasi-static pore-network modeling for simulating the transport of hydrogen in networks with box-shaped pores and square cylinder throats. The dynamic pore-network modeling results are compared with quasi-static pore-network modeling, and a good agreement is observed when the simulations reach steady-state, for a capillary number of Nc≤10−7. This finding suggests that the quasi-static approach can be used as a reliable and efficient method for studying hydrogen transport in similar networks.

Theoretical analysis of structural, electronic, optical, and thermoelectric properties of XNaH2 (X = K, Rb) hybrid metal hydride composites

Abstract Hydrogen storage has become a global challenge for scientists of this era because it is an economical, clean, and non-pollutant element present in nature. In the present work, the DFT study of structural, electronic, optical, and thermoelectric properties of metal hydride XNaH2 (X = K, Rb) has been performed. Both of these materials are found stable in ambient conditions having semiconductor nature. The optical properties have been investigated in terms of dielectric function, refractive index, absorption coefficient, extinction coefficient, optical conductivity, reflectivity, and energy loss function. The better thermoelectric profile of these composites computed from the BoltzTraP2 code to shows their remarkable thermoelectric response between 200 to 950 K temperature. Remarkably, the computational calculations of these hydrides are made, which could lead to outstanding advancements in applications for hydrogen storage.

Hydrogen Storage Studies of Nanocomposites Derived From O‐Ethyl‐S‐((5‐Methoxy‐1H‐Benzo[d]Imidazol‐2‐Yl)Carbonothioate (OESMBIC) With ZnO and TiO2 Nanoparticles

ABSTRACT5‐Methoxy‐2‐mercaptobenzamidazole was used to synthesize O‐ethyl‐S‐(5‐methoxy‐1H‐benzo[d]imidazol‐2‐yl) carbonothioate (OESMBIC) by the reaction with chloroacetic acid ethyl ester in a KOH solution. The reaction product (OESMBIC) was characterized using Fourier transform infrared (FTIR), melting point, and 1H‐NMR. The characteristic results prove the formation of the target compound with high purity. Furthermore, the work includes the synthesis of ZnO and TiO2 nanoparticles via chemical methods in the high alkalinity solution. These nanoparticles were used to synthesize two novel nanocomposites named OESMBIC‐ZnO and OESMBIC‐TiO2. The synthesized nanocomposites were characterized by FTIR, SEM, EDX, TEM, and XRD. The results prove that the prepared titanium oxide as nanotubes with diameters ranging between 20 and 35 nm decorated with OESMBIC. The results prove that ZnO in OESMBIC‐ZnO was found as nanorods with different lengths and diameters of 40–65 nm decorated with OESMBIC molecules. The as‐prepared compounds; OESMBIC, OESMBIC‐ZnO, and OESMBIC‐TiO2 were used for the hydrogen storage application using the VTI method. The results prove that the addition of ZnO and TiO2 nanoparticles enhanced the storage ability of OESMBIC as the OESMBIC gave only 0.50 wt% at an equilibrium pressure of 40 bar, while it reached 2.40 and 4.37 wt% at equilibrium pressures of 60 and 75 bar for OESMBIC‐ZnO and OESMBIC‐TiO2, respectively.

Exploring the structural, electronic, mechanical, magnetic and optical properties of Cs-based hydride-perovskites CsXH3 (X = Cr, Mn) for hydrogen storage application

Low cast hydride-perovskites are more efficient in power conversion and for energy storage. Here in, structural investigation, electronic, mechanical and optical properties of hydrogen based CsXH3 (X = Cr, Mn) compounds using the density functional theory. The result shows that both materials crystallize into cubic structure. The thermodynamic and dynamic stabilities are conformed through formation energy and phonon dispersion curve. The optimized lattice constants are 3.52 Å and 3.54 Å for CsCrH3 and CsMnH3 respectively. Both materials are found to be half metallic in nature. IR-Elast package are used to obtain elastic constants. The elastic study presents that both materials are ductile and have anisotropic nature. The optical parameters are studied in the range of 0–10 eV. The optical results show that both materials have an excellent optical absorption. The values obtained of gravimetric hydrogen storage capacity for these compounds are 1.55 % and 1.58 % for CsMnH3 and CsCrH3 respectively indicating that these materials can be an excellent candidate for hydrogen energy storage.

High entropy alloys for hydrogen storage applications: A machine learning-based approach

Hydrogen is a clean energy carrier and has potential applications in energy storage, power generation, and transportation. This study explores the efficient and safe storage of hydrogen, particularly through solid-state methods using high entropy alloys (HEAs). HEAs have garnered attention for their versatility in tailoring properties for hydrogen storage. The integration of Machine Learning (ML) in designing HEAs offers an expedited approach, analyzing datasets and predicting material properties to enhance storage capacity, kinetics, and stability. Despite significant progress, the study acknowledges certain research limitations, particularly its relatively narrow focus on applying ML to HEAs for hydrogen storage. One of the biggest challenges with HEAs is their complexity, which.necessitates larger datasets to develop accurate predictive models. Collecting and analyzing existing HEA data for hydrogen storage using ML techniques is the main objective. Using algorithms like support vector regression (SVR), K-nearest (KNN), and random forest (RF), hydrogen-to-metal ratio (H/M) and valence electron configuration (VEC) are accurately predicted. The study proposes alloys with potential for HEA formation, identifying 741 with quaternary and 631 with quinary HEAs. These compositions are newly proposed and do not yet exist. Out of these, 774 HEAs are identified as potential candidates for hydrogen storage applications. Applying ML techniques, the selection process is more efficient, reducing the dependency on time-consuming experiments and making it easier to discover promising candidates.

Fabrication and characterization of rippled graphene/LDPE composites with enhanced hydrogen barrier properties

Hydrogen plays a pivotal role as a sustainable energy carrier, but the cost-effective and efficient production of gas barrier materials for hydrogen storage still poses a considerable challenge. In this research, we investigate the hydrogen barrier properties of nanocomposites based on low-density polyethylene (LDPE) filled with varying concentrations (0–5 wt%) of rippled graphene. The low-density polyethylene rippled graphene (LPRG) nanocomposites were prepared by drop-casting a suspension of graphene with LDPE dissolved in Toluene, which resulted in a uniform dispersion of rippled graphene within the LDPE matrix. Mechanical testing revealed notable improvements in tensile strength (+40%) and Young's modulus (+120%), confirming the reinforcing effect of rippled graphene in the polymer matrix. Results from the thermogravimetric analysis showed that the addition of rippled graphene significantly increased the thermal stability of the material, reporting an increase of 77 °C in the thermal degradation temperature at a nanofiller loading of 1 wt%. Additionally, the incorporation of rippled graphene in the composite improved the thermal conductivity by 161 %. Moreover, it resulted in an electrically percolated network at a critical nanofiller loading of 1 wt%, contributing to enhanced electrostatic discharge safety. Finally, gas permeability tests unveiled a 50% reduction in hydrogen permeability of LPRG with graphene content of 5 wt% compared to pristine LDPE, making graphene/LDPE composites a superior choice for sustainable and efficient hydrogen storage applications.

Density functional analysis of structural, mechanical, electronic, and hydrogen storage properties of thermodynamically stable lead-free hydrides [formula omitted](X = Cs, Fr): A perspective of clean energy and fuel

A density functional theory based calculations are performed to investigate structural, hydrogen storage, mechanical, electronic and thermodynamical properties of lead-free hydride perovskites XGeH3 (X=Cs, Fr). The optimized lattice constant and hence volume against the minimum energy is obtained and found to be 4.176 Å and 4.184 Å for CsGeH3 and FrGeH3 respectively. The gravimetric and volumetric hydrogen storage capacity of 1.43% and 1.00%, 72.81(g.H2/L) and 73.21(g.H2/L) for CsGeH3 and FrGeH3 respectively. The density of states and electronic band structure predicted the metallic nature of both hydrides which was affirmed by the Fermi Surfaces. The calculation of Poisson’s, Pugh’s ratio and Cauchy’s pressure suggested their brittle nature. The Debye temperature decreases with the increase of temperature while volume and entropy increase by increasing applied temperature. The present study shows the potential of lead-free hydride perovskites in hydrogen storage applications due to rather suitable gravimetric hydrogen capacity and high stability.