Hydrogen Storage Capacity Research Articles

Mechanism of hot‐spot formation of emulsion explosives sensitized by hydrogen‐storage glass microballoons

AbstractIn order to investigate the primary factors influencing hot‐spot formation in emulsion explosives sensitized by hydrogen‐storage glass microballoons (GMBs), we conducted impact calculations on hydrogen‐storage GMBs. The calculations focused on tracking two main mechanisms: the brittle collapse of GMBs and the adiabatic compression of internal gas. Various parameters were considered, including loading pressures, initial porosities, gas types, and initial gas pressures. Our findings indicate that the contribution of brittle collapse to hot‐spot formation is negligible, while adiabatic compression emerges as the predominant intrinsic mechanism for hot‐spot ignition in GMB‐sensitized emulsion explosives. Moreover, we observed that the ignition time remains similar for low‐pressure nitrogen and high‐pressure hydrogen. The addition of hydrogen does not result in an increased number of hot‐spots; however, it elevates the energy of each individual hot‐spot, thereby enhancing power delivery. Optimal selection of GMB size is crucial for hot‐spot formation and hydrogen storage. GMBs that are excessively large are prone to shell breakage, while overly small GMBs have limited hydrogen storage capacity. GMBs within the size range of 20 μm to 100 μm are deemed more suitable for emulsion explosives.

Exploring microstructure variations and hydrogen storage characteristics in TiVNbCrNi high-entropy alloys with different Ni incorporation

In recent years, high-entropy alloys (HEAs), as a novel class of hydrogen storage materials, have been deemed highly promising due to their extensive compositional tunability and the unique high entropy effects. This study aims to enhance the comprehensive hydrogen storage performance of the TiVNbCr-based HEA by introducing Ni. The effects of Ni addition on the microstructural evolution of the alloy and its impact on activation properties, hydrogen absorption and desorption kinetics, thermodynamics, and cycling performance under the complex physicochemical environment of multiple principal elements was systematically investigated. The findings indicate that Ni addition shortens the activation incubation period of the alloy but more Ni reduces the intrinsic hydrogen absorption kinetics. In the Ti25V30Nb10Cr33Ni2 alloy, a high reversible hydrogen storage capacity of up to 2.2 wt% at room temperature was achieved, surpassing most of the currently reported body-centered cubic (BCC)-structured high-entropy hydrogen storage alloys. Furthermore, the influence of Ni on the alloy's hydrogen desorption kinetics and cycling hydrogenation performance was studied. Results from 110 cycles of testing reveal that the introduction of Ni-induced Laves phases can act to relax stress, thereby reducing strain accumulation during the hydrogen absorption and desorption cycling process. This could provide guidance for the design of high-entropy hydrogen storage alloys with extended cycling lifetimes.

Magnesium-Based Hydrogen Storage Alloys: Advances, Strategies, and Future Outlook for Clean Energy Applications.

Magnesium-based hydrogen storage alloys have attracted significant attention as promising materials for solid-state hydrogen storage due to their high hydrogen storage capacity, abundant reserves, low cost, and reversibility. However, the widespread application of these alloys is hindered by several challenges, including slow hydrogen absorption/desorption kinetics, high thermodynamic stability of magnesium hydride, and limited cycle life. This comprehensive review provides an in-depth overview of the recent advances in magnesium-based hydrogen storage alloys, covering their fundamental properties, synthesis methods, modification strategies, hydrogen storage performance, and potential applications. The review discusses the thermodynamic and kinetic properties of magnesium-based alloys, as well as the effects of alloying, nanostructuring, and surface modification on their hydrogen storage performance. The hydrogen absorption/desorption properties of different magnesium-based alloy systems are compared, and the influence of various modification strategies on these properties is examined. The review also explores the potential applications of magnesium-based hydrogen storage alloys, including mobile and stationary hydrogen storage, rechargeable batteries, and thermal energy storage. Finally, the current challenges and future research directions in this field are discussed, highlighting the need for fundamental understanding of hydrogen storage mechanisms, development of novel alloy compositions, optimization of modification strategies, integration of magnesium-based alloys into hydrogen storage systems, and collaboration between academia and industry.

The improvement of hydrogen storage capacity via bubbles nucleated in ice-like nanotubes

The existing methods of hydrogen storage bottlenecked advancements in its commercialization on an industrial scale. Here, the hydrogen storage capacity via the hydrogen clathrate hydrate in ice Ih (HCHinIh) with the aid of nanobubbles is further improved to 3.442–3.494 wt% from the previous 3.441 wt%. These nanobubbles are designedly arranged within 0.5 mm diameter individual ice spheres which initially pack in simple cubic form, and then used to synthesize the hydrogen clathrate hydrate as does HCHinIh. The total volume of nanobubbles is adjustable by deploying their different space layouts. In addition, we propose that the bubble formation is driven by transforming the pre-melted quasi-liquid layer (PMQLL) to solid ice-like in an ice-like nanotube, which is a structure comprised of PMQLL and ice surrounding PMQLL (PMQLL-ice) analogous to a carbon nanotube-graphene sheet (CNT-GS) structure, where the interaction energy related to O–O and O–H in PMQLL-ice is 0.08–6.17 times that of C–O and C–H in the CNT-GS structure.

Computational investigation of NLi4-cluster decorated phosphorene for reversible hydrogen storage

The use of lithium-decorated phosphorene for hydrogen storage is significantly limited due to metal aggregation on substrates. Despite considerable research and effort in the literature to address this issue, no one has succeeded in enhancing the capacity of phosphorene through metal atom decoration. Based on density functional theory (DFT) and AIMD simulations, superalkali NLi4-decorated black phosphorene monolayer is developed as a new hydrogen storage solid-state material. Our results show that the NLi4-cluster exhibits a significant binding energy of −3.18 eV when attached to one side of the phosphorene on a stable site, indicating a strong affinity between the NLi4-cluster and phosphorene surfaces. Moreover, 2(NLi4)@phosphorene can store up to 30H2 molecules with a suitable average hydrogen adsorption-energy and a maximum hydrogen storage capacity of 6.8 wt%. Using the van't Hoff equation and increasing the pressure, we find that the desorption temperature is higher than the critical point for hydrogen. AIMD simulations at different temperatures demonstrate the thermal stability of the hydrogenated 2(NLi4)@phosphorene and the H2 desorption process. The findings of the present study suggest the potential utilization of the 2(NLi4)@phosphorene adsorptive material for hydrogen storage applications.

Electronic, elastic, and thermodynamic properties of complex hydrides XAlSiH (X = Sr, Ca, and Ba) intended for hydrogen storage: an ab-initio study

The mechanical and thermodynamic properties of polyanionic hydrides XAlSiH (X = Sr, Ca, and Ba) were evaluated using density functional theory (DFT). The thermal parameters of XAlSiH hydrides, such as the Grüneisen parameter γ, heat capacity, and thermal expansion coefficient, were computed for the first time. The quasi-harmonic Debye model was used to determine these parameters over a range of pressures (0–40 GPa) and temperatures (0–1000 K). The gravimetric hydrogen storage capacities for BaAlSiH, SrAlSiH, and CaAlSiH were found to be 0.52%, 0.71%, and 1.05%, respectively. The hydrogen desorption temperatures for these compounds were also simulated at 748.90 K, 311.57 K, and 685.40 K. Furthermore, semiconducting behavior with an indirect bandgap value between 0.2 and 0.7 eV was exhibited by these compounds using the GGA and LDA approximation, and between 0.7 and 1.2 eV using the mBJ-GGA and mBJ-LDA approximation. Accurate elastic constants for single crystals were obtained from the calculated stress–strain relationships. The elastic constants for the XAlSiH compounds were significantly higher than those for other hydrides. The [001] direction was more compressible than the [100] direction in the hexagonal structure of XAlSiH. A lower bulk modulus than metallic hydrides was exhibited by these materials, indicating that XAlSiH compounds (X = Sr, Ca, and Ba) were highly compressible. The melting temperature for CaAlSiH was higher than that for SrAlSiH and BaAlSiH. Consequently, the decomposition temperature for XAlSiH (X = Sr and Ba) at which hydrogen was released from a fuel cell was lower than that for CaAlSiH. The bonding behavior of CaAlSiH was more directional than that of SrAlSiH and BaAlSiH. Brittle materials were XAlSiH (X = Sr, Ca, and Ba). Our PBE calculations yield linear compressibility and orientation-dependent Young’s modulus. Materials composed of hexagonal XAlSiH (where X represents Sr, Ca, or Ba elements) exhibit anisotropy in Young’s modulus but isotropy in bulk modulus.

Chemical material as a hydrogen energy carrier: A review

In light of climate change imperatives, there arises a critical need for technological advancements and research endeavors towards clean energy alternatives to replace conventional fossil fuels. Additionally, the development of high-capacity energy storage solutions for global transportability becomes paramount. Hydrogen emerges as a promising environmentally sustainable energy carrier, devoid of carbon dioxide emissions and possessing a high energy density per unit mass. Its versatile applicability spans various sectors including industry, power generation, and transportation. However, the commercialization of hydrogen necessitates further technological innovations. Notably, high-pressure compression for hydrogen storage presents safety challenges and inherent limitations in storage capacity about 30%–50% lost production of hydrogen. Consequently, substantial research endeavors are underway in the domain of material-based chemical hydrogen storage that reactions to occur at temperatures below 200 ℃. This approach enables the utilization of existing infrastructure, such as fossil fuels and natural gas, while offering comparatively elevated hydrogen storage capacities. This study aims to introduce recent investigations concerning the synthesis and decomposition mechanisms of chemical hydrogen storage materials, including methanol, ammonia, and Liquid Organic Hydrogen Carrier (LOHC).

Recent Advances in the Preparation Methods of Magnesium-Based Hydrogen Storage Materials.

Magnesium-based hydrogen storage materials have garnered significant attention due to their high hydrogen storage capacity, abundance, and low cost. However, the slow kinetics and high desorption temperature of magnesium hydride hinder its practical application. Various preparation methods have been developed to improve the hydrogen storage properties of magnesium-based materials. This review comprehensively summarizes the recent advances in the preparation methods of magnesium-based hydrogen storage materials, including mechanical ball milling, methanol-wrapped chemical vapor deposition, plasma-assisted ball milling, organic ligand-assisted synthesis, and other emerging methods. The principles, processes, key parameters, and modification strategies of each method are discussed in detail, along with representative research cases. Furthermore, the advantages and disadvantages of different preparation methods are compared and evaluated, and their influence on hydrogen storage properties is analyzed. The practical application potential of these methods is also assessed, considering factors such as hydrogen storage performance, scalability, and cost-effectiveness. Finally, the existing challenges and future research directions in this field are outlined, emphasizing the need for further development of high-performance and cost-effective magnesium-based hydrogen storage materials for clean energy applications. This review provides valuable insights and references for researchers working on the development of advanced magnesium-based hydrogen storage technologies.

A density functional theory study of hydrogen storage on Ni and Pd doped hetero GeC nanotubes

AbstractUsing ab‐initio DFT based simulations, the hydrogen storage capacity of transition metal (TM = Ni, Pd) decorated doped germanium carbide nanotubes (GeCNTs) with heteroatoms (B, N, Ga, and As) has been examined. The study reveals that each Ni atom bonded on GeCB, GeCN, GeCGa, and GeCAs can attach at the most of 3H2, 2H2, 4H2, and 5H2 molecules with an average binding energy of −.36, −.40, −.32, and −.37 eV/H2, respectively. When doped GeCNTs are fully decorated with Ni atoms, their gravimetric hydrogen storage capacities are around 4.05, 2.73, 5.38, and 6.57 wt%, respectively. The desorption temperature of the systems is 460, 511, 404, and 473 K, respectively. When doped GeCNTs are fully decorated with Pd atoms, their gravimetric hydrogen storage capacities are around 2.07, 3.07, 4.05, and 3.07 wt%, respectively. These findings demonstrate that doped‐GeC adorned with Pd does not satisfy US DOE hydrogen storage requirements. The molecular dynamic (MD) calculations are utilized to examine the stability of the considered structures. The results demonstrate that Ni‐adorned GeCAs are a suitable material for hydrogen storage, which will motivate scientists to fabricate GeCAs‐based fuel cell devices.

Investigation for the hydrogen storage properties of XCrH3 (X=Na, K) and KYH3(Y[dbnd]Mo, W) perovskite type hydrides based on first-principles

Perovskite type hydrides have emerged as a focal point in hydrogen storage applications as potential candidates in recent years. However, the currently synthesized perovskite hydrogen storage materials suffer from high hydrogen desorption temperatures and unstable reactions. To identify promising perovskite hydrogen storage materials, this study explores the hydrogen storage properties of XCrH3 (X = Na, K) and KYH3 (YMo, W) based on first-principles (FPs) calculations. The results indicate that NaCrH3 and KCrH3 exhibit half-metallic properties, while KMoH3 and KWH3 are metallic materials with high hydrogen storage safety. Mechanical property analysis reveals that NaCrH3 exhibits the highest hardness, indicating better stability for hydrogen storage. Thermodynamic analysis shows that KCrH3 has a lower hydrogen desorption temperature than the other three compounds, with NaCrH3 having the second-lowest. The gravimetric hydrogen storage capacities of NaCrH3, KCrH3, KMoH3, and KWH3 are 3.85 wt%, 3.21 wt%, 2.19 wt%, and 1.34 wt%, respectively. Overall, NaCrH3 demonstrates superior gravimetric hydrogen storage capacity, stability, and safety, making it a promising candidate for new perovskite type hydrogen storage materials.

Palladium effect on electrochemical hydrogen storage properties of nanoporous silicon

Coating porous silicon with metal catalysts such as palladium is considered a reliable method to improve the hydrogen storage performance of electrodes. Here, in order to evaluate the most effective use of Pd nanoparticle or Pd thin film, Pd nanoparticles with a size of 36 nm obtained by electroless method, and a Pd thin film with a thickness of 30 nm deposited by thermal evaporation were coated onto nanoporous silicon sample” and studied. The Pd deposits were confirmed by Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The obtained electrode materials: PS and Pd/PS were characterized by different electrochemical characterization techniques: cyclic voltammetry (CV) and galvanostatic charge/discharge. The results showed that Pd NPs/PS achieved the highest hydrogen storage capacity with a value of 425.9 mA h g-1. These results confirm that using Pd nanoparticles as catalyst metal is more suitable to improving the hydrogen storage capacity of electrode materials.

Hydrogenation-controlled band engineering of dumbbell graphene

The stability of the dumbbell structure has been confirmed by previous theory and experiment. Based on first-principles calculations, we proposed hexagonal dumbbell graphene (HDB C10) and rectangular dumbbell graphene (RDB C10) monolayers containing periodically raised C (CR) atoms. They turn out to have high mobility semiconductor properties. By adsorbing H atoms on these CR atoms, their band structures can be widely tuned from semiconductor to semimetal. When considering adsorption of two/four H atoms on the unit cell of the dumbbell structure, the bandgap can be increased, and isolated flat band structures can be obtained by further adding or removing H atoms. Remarkably, two different Dirac band structures can be found in the HDB/RDB C10H2-I monolayers. The HDB C10H2-I shows a Dirac cone with isotropic Fermi velocities, while the RDB C10H2-I monolayer exhibits a quasi-one-dimensional Dirac nodal line with varying Fermi velocities along the XS path. Tight-binding (TB) models are constructed including nearest neighbor (NN) and next NN hopping in order to understand our DFT results. These TB models are related to the Su-Schrieffer-Heeger model, and are able to explain the tunable topological properties of the RDB C10H2-I monolayer. They not only are able to explain the different kinds of Fermi velocity, but also can predict the emergence of topological edge states, providing a good platform for research on Dirac fermions. The HDB/RDB C10 monolayer exhibits more freedom of tunable band structures and more stable hydrogen storage capacity, making it superior to graphene. Finally, possible experimental synthesis paths of these DB monolayers are provided.

The relationship between hydrogen storage capacity and 4d transition metal-carbon surface binding energy

This study explores the correlation between the strength of 4d-transition metal (TM)/surface binding energy (BE) and the hydrogen storage capacity in decorated (TM@CNF) and doped (TM/CNF) carbon nanoflakes. The findings reveal smaller TM-CNF distances and larger BE for doped cases. These TM-CNF bond characteristics impact the storage capacity, with doped cases outperforming in Mo/CNF and Tc/CNF and decorated in Y@CNF and Zr@CNF scenarios. This contrasting performance underscores the difficulty in finding a surface/dopant combination for efficient storage, where the BE cannot be weak due to its stability and also cannot be too strong due to the loss of storage capacity.

Design of a new nanocomposite based on Keggin-type [ZnW12O40]6− anionic cluster anchored on NiZn2O4 ceramics as a promising material towards the electrocatalytic hydrogen storage

Extensive research efforts have been dedicated to developing electrode materials with high capacity to address the increasing complexities arising from the energy crisis. Herein, a new nanocomposite was synthesized via the sol–gel method by immobilizing K6ZnW12O40 within the surface of NiZn2O4. ZnW12O40@NiZn2O4 was characterized by FT-IR, UV–Vis, XRD, SEM, EDX, BET, and TGA-DTG methods. The electrochemical characteristics of the materials were examined using cyclic voltammogram (CV) and charge–discharge chronopotentiometry (CHP) techniques. Multiple factors affecting the hydrogen storage capacity, including current density (j), surface area of the copper foam, and the consequences of repeated cycles of hydrogen adsorption–desorption were evaluated. The initial cycle led to an impressive hydrogen discharge capability of 340 mAh/g, which subsequently increased to 900 mAh/g after 20 cycles with a current density of 2 mA in 6.0 M KOH medium. The surface area and the electrocatalytic characteristics of the nanoparticles contribute to facilitate the formation of electrons and provide good diffusion channels for the movement of electrolyte ions throughout the charge–discharge procedure.

Physical properties of the XScH3 (X: Ca, and Mg) perovskite hydrides and their hydrogen storage applications

We conducted a comprehensive investigation into the structural, mechanical, electronic, magnetic, thermodynamic, optical, and hydrogen storage properties of the novel XScH3 (X: Ca and Mg) perovskite hydrides by using density functional theory (DFT). Our calculations of the cohesive energy and elastic constants demonstrated that XScH3 compounds exhibit both thermal and mechanical stability. The metallic nature of current materials is based on the investigation of the electronic band structure and total density states. The analysis of Pugh's ratio (B/G) indicated that these hydrides were ductile materials. Furthermore, it was found that their bonding type was primarily ionic. These substances have been classified as conductors with antiferromagnetic qualities in terms of their magnetic properties. Furthermore, these materials exhibited promising effects on optical properties such as conductivity, absorption, dielectric function, and refractive index. Our predictions revealed that CaScH3 was found to be optically superior hydride. The dynamic stability of these crystals was assessed by analyzing their phonon dispersion curves and by molecular dynamics simulations. Additionally, we studied their thermal properties, including heat capacity, entropy, energy, and free energy, as functions of temperature. Furthermore, our study investigated the hydrogen storage capacity of XScH3 compounds, with CaScH3 and MgScH3, demonstrating hydrogen storage capacities of 3.43 wt% and 4.18 wt%, respectively. This study marks the first exploration of XScH3 perovskite hydrides and offers new options for hydrogen storage materials.

Molecular dynamics simulation of hydrogen adsorption and diffusion characteristics in graphene pores

Carbon structures have been shown to be potentially efficient hydrogen storage media, but the micro adsorption/diffusion kinetic properties of hydrogen storage are still unclear. We investigated the adsorption of H2 in carbonaceous nanoporous by molecular dynamics simulations. It was found that the hydrogen molecules were completely adsorbed when the pore size was 1 nm, and existed in both adsorbed and free forms when the pore size was 2–6 nm, and the adsorption was in a saturated state, with the absolute adsorption amount keeping constant. Modification of functional groups on the inner side of graphene pores reduces the hydrogen storage capacity, and this effect becomes more and more obvious with decreasing pore size, especially for 1 nm pores. The total adsorption amount of H2 in 1 nm graphene pores was 0.01315 × 10−3 mol/m2, which was 3.8846 times that of graphene oxide pore. The hydrogen adsorption effect on different surfaces is: G > GO(-O-) > GO(-OH) > GO(-O-/OH). The results of this study are helpful to further understand the physical adsorption mechanism of molecular hydrogen on carbonaceous materials.

Evaluation of hydrogen storage capacity of two-dimensional Sc2N MXene: A DFT study

In this work, the efficiency of hydrogen storage on Sc2N MXenes monolayer is systematically investigated using first-principles calculations. After determining the structural stability of designed monolayer, adsorption sites for the storage of hydrogen atoms (H) and molecules (H2) are identified. The calculated binding energies have indicated that the hydrogen atoms have favorable adsorption at the center or H site of the Sc atoms and hydrogen molecules are found to be the most stable when adsorbed on the top/T site of Sc atoms. The binding energy assessment identified the chemisorption for hydrogen atoms and Kubas-type interactions for H2. To further ascertain the suitability of the Sc2N monolayer for hydrogen storage various analyses including binding energy, partial density of states (PDOS), electron localization function (ELF), Mullikan charge analysis and Hirshfeld charge analysis are conducted. In order to determine the thermal stability of the Sc2N monolayer, desorption temperature with respect to pressure and molecular dynamics study has also been conducted and found the monolayer thermally stable. Desorption isotherms condition with increasing pressure confirms the gravimetric storage uptake. The obtained results have revealed that the hydrogen storage capacity considered monolayer has reached up to 10.8 wt%, which is reasonably high. Hence, the obtained results of hydrogen atom and molecules adsorption have clearly established that Sc2N monolayer is as an exemplary, stable, reliable and efficient medium for hydrogen storage applications.

Unstable Metal Hydrides for Possible On-Board Hydrogen Storage

Hydrogen storage in general is an indispensable prerequisite for the introduction of a hydrogen energy-based infrastructure. In this respect, high-pressure metal hydride (MH) tank systems appear to be one of the most promising hydrogen storage techniques for automotive applications using proton exchange membrane (PEM) fuel cells. These systems bear the potential of achieving a beneficial compromise concerning the comparably large volumetric storage density, wide working temperature range, comparably low liberation of heat, and increased safety. The debatable term “unstable metal hydride” is used in the literature in reference to metal hydrides with high dissociation pressure at a comparably low temperature. Such compounds may help to improve the merits of high-pressure MH tank systems. Consequently, in the last few years, some materials for possible on-board applications in such tank systems have been developed. This review summarizes the state-of-the-art developments of these metal hydrides, mainly including intermetallic compounds and complex hydrides, and offers some guidelines for future developments. Since typical laboratory hydrogen uptake measurements are limited to 200 bar, a possible threshold for defining unstable hydrides could be a value of their equilibrium pressure of peq > 200 bar for T < 100 °C. However, these values would mark a technological future target and most current materials, and those reported in this review, do not fulfill these requirements and need to be seen as current stages of development toward the intended target. For each of the aforementioned categories in this review, special care is taken to not only cover the pioneering and classic research but also to portray the current status and latest advances. For intermetallic compounds, key aspects focus on the influence of partial substitution on the absorption/desorption plateau pressure, hydrogen storage capacity and hysteresis properties. For complex hydrides, the preparation procedures, thermodynamics and theoretical calculation are presented. In addition, challenges, perspectives, and development tendencies in this field are also discussed.

The reversal of carbonate wettability via alumina nanofluids: Implications for hydrogen geological storage

Underground hydrogen storage (UHS) has been recognized as a key enabler of the industrial-scale implementation of a hydrogen-based economy. However, the efficiency and storage capacity of hydrogen (H2) in carbonate aquifers can be influenced by the presence of organic acids. Nevertheless, the existing literature contains few investigations of H2/calcite/brine wettability and the influence of organic acids on H2 storability in carbonate reservoirs. Therefore, the present study examines the influence of stearic acid on the dynamic H2/brine wettability of calcite substrates (as a proxy of carbonate formation) under various geological conditions (0.1–20 MPa at 323 K), equilibrated in 10 wt% NaCl brine. In addition, the application of various alumina nanofluid concentrations (0.05, 0.1, 0.25, and 0.75 wt%) is evaluated under the same experimental conditions for enhancing the organic-aged calcite wettability. The results demonstrate a significant impact of stearic acid on the dynamic (advancing and receding) contact angles of the calcite substrates, thereby resulting in a shift from intermediate water-wet to H2-wet conditions, representing an unfavorable state for H2 geological storage. Conversely, the application of alumina nanofluid on the organic-aged calcite substrate enhances the H2/brine/calcite wettability towards an intermediate water-wet state, which is more favorable for H2 residual trapping in carbonate formations. The optimal concentration of alumina nanofluid for the wettability modification of the organically aged calcite samples is found to be 0.25 wt%. These findings highlight the influence of organic acid contamination and the potential of alumina nanofluid application in enhancing H2 geo-storage conditions in carbonate reservoirs.

Enhanced hydrogen storage of single-layer blue phosphorus by synergistic effect between doped lightweight elements and grafted lithium atoms

Single-layer blue phosphorus (SLBP) has displayed charming photoelectric performances, but its property in hydrogen storage is not outstanding due to the weak interactions. To expand the application of SLBP in hydrogen storage, we attempt to screen SLBP-based materials with stable structures and strong polarity using density functional theory by doping lightweight elements and grafting alkali metal atoms. The simulation results indicate that the lightweight elements (B, C, N, O and F) doped SLBP systems have more stable structures due to the strong orbital interaction than pure SLBP, and exhibit electron deficient characteristics. Compared to the pure SLBP, the H2 adsorption energies of the doped systems improve and range from 0.05 to 0.09 eV, but it still cannot meet the requirements of ideal hydrogen storage. Therefore, the lightweight element doped SLBP systems are further grafted by Li atom. Under the synergistic effect of doping lightweight elements and grafting Li atoms, H2 molecules are strongly polarized, and the corresponding adsorption energies of H2 reach to 0.16, 0.26, 0.28, 0.30, and 0.10 eV, respectively. It is worth emphasizing in the C-doped SLBP system that the hydrogen storage capacity of reaches 5.53 wt% for each Li atom adsorbs one hydrogen molecule and the corresponding adsorption energy is 0.23 eV/H2 when the ratio of C to P atoms increases to 6:26. For each Li atom adsorbs two hydrogen molecules in the same hydrogen storage system, the hydrogen storage capacity reaches 10.48 wt% with 0.18 eV/H2 adsorption energy. We hope these results can provide theoretical basis and scientific guidance for searching for SLBP-based materials with excellent hydrogen storage performances at ambient temperature.