Showing papers on "Hydrogen storage published in 2019"

Hydrogen Storage for Mobility: A Review

Abstract: Numerous reviews on hydrogen storage have previously been published. However, most of these reviews deal either exclusively with storage materials or the global hydrogen economy. This paper presents a review of hydrogen storage systems that are relevant for mobility applications. The ideal storage medium should allow high volumetric and gravimetric energy densities, quick uptake and release of fuel, operation at room temperatures and atmospheric pressure, safe use, and balanced cost-effectiveness. All current hydrogen storage technologies have significant drawbacks, including complex thermal management systems, boil-off, poor efficiency, expensive catalysts, stability issues, slow response rates, high operating pressures, low energy densities, and risks of violent and uncontrolled spontaneous reactions. While not perfect, the current leading industry standard of compressed hydrogen offers a functional solution and demonstrates a storage option for mobility compared to other technologies.

Hydrogen Fuel Cell Vehicles; Current Status and Future Prospect

Abstract: The hazardous effects of pollutants from conventional fuel vehicles have caused the scientific world to move towards environmentally friendly energy sources. Though we have various renewable energy sources, the perfect one to use as an energy source for vehicles is hydrogen. Like electricity, hydrogen is an energy carrier that has the ability to deliver incredible amounts of energy. Onboard hydrogen storage in vehicles is an important factor that should be considered when designing fuel cell vehicles. In this study, a recent development in hydrogen fuel cell engines is reviewed to scrutinize the feasibility of using hydrogen as a major fuel in transportation systems. A fuel cell is an electrochemical device that can produce electricity by allowing chemical gases and oxidants as reactants. With anodes and electrolytes, the fuel cell splits the cation and the anion in the reactant to produce electricity. Fuel cells use reactants, which are not harmful to the environment and produce water as a product of the chemical reaction. As hydrogen is one of the most efficient energy carriers, the fuel cell can produce direct current (DC) power to run the electric car. By integrating a hydrogen fuel cell with batteries and the control system with strategies, one can produce a sustainable hybrid car.

Energy-based descriptors to rapidly predict hydrogen storage in metal–organic frameworks

Abstract: The low volumetric density of hydrogen is a major limitation to its use as a transportation fuel. Filling a fuel tank with nanoporous materials, such as metal–organic frameworks (MOFs), could greatly improve the deliverable capacity of these tanks if appropriate materials could be found. However, since MOFs can be made from many combinations of metal nodes, organic linkers, and functional groups, the design space of possible MOFs is enormous. Experimental characterization of thousands of MOFs is infeasible, and even conventional molecular simulations can be prohibitively expensive for large databases. In this work, we have developed a data-driven approach to accelerate materials screening and learn structure–property relationships. We report new descriptors for gas adsorption in MOFs derived from the energetics of MOF–guest interactions. Using the bins of an energy histogram as features, we trained a sparse regression model to predict gas uptake in multiple MOF databases to an accuracy within 3 g L−1. The interpretable model parameters indicate that a somewhat weak attraction between hydrogen and the framework is ideal for cryogenic storage and release. Our machine learning method is more than three orders of magnitude faster than conventional molecular simulations, enabling rapid exploration of large numbers of MOFs. As a case study, we applied the method to screen a database of more than 50 000 experimental MOF structures. We experimentally validated one of the top candidates identified from the accelerated screening, MFU-4l. This material exhibited a hydrogen deliverable capacity of 47 g L−1 (54 g L−1 simulated) when operating at storage conditions of 77 K, 100 bar and delivery at 160 K, 5 bar.

Review on hydrogen storage materials and methods from an electrochemical viewpoint

Abstract: Hydrogen being clean energy source is an effective substitute to current fossil fuels. Present day advancement in hydrogen economy field has motivated researchers to work in green energy field. Different types of methods are in use to store hydrogen. Our review focuses initially on various types of sustainable and non-renewable energy sources, then with emphasis towards hydrogen economy, we discuss in details about it. Hydrogen is efficient candidate amongst vivid sustainable source of energy. Hydrogen advantages and its applications in different fields are covered. Initially discussing different methods to synthesize hydrogen, we shift towards the hydrogen storage methods. Amongst all the hydrogen storage methods, electrochemical method is best, as hydrogen is generated, stored in situ at normal pressure and temperature conditions. Different methods can be used to study hydrogen storage by electrochemical means. Various materials that can efficiently store hydrogen, were covered. Hydrogen is most common fuel in fuel cell, hence classification of hydrogen fuel cells and their relevance with respect to stationary and portable fields are covered.

Scalable and Physical Synthesis of 2D Silicon from Bulk Layered Alloy for Lithium-Ion Batteries and Lithium Metal Batteries.

Abstract: Owing to its distinctive structure and properties, 2D silicon (2DSi) has been widely applied in hydrogen storage, sensors, electronic device, catalysis, electrochemical energy storage, etc. However...

Complex Hydrides for Energy Storage, Conversion, and Utilization.

Abstract: Functional materials are the key enabling factor in the development of clean energy technologies. Materials of particular interest, which are reviewed herein, are a class of hydrogenous compound having the general formula of M(XHn )m , where M is usually a metal cation and X can be Al, B, C, N, O, transition metal (TM), or a mixture of them, which sets up an iono-covalent or covalent bonding with H. M(XHn )m is generally termed as a complex hydride by the hydrogen storage community. The rich chemistry between H and B/C/N/O/Al/TM allows complex hydrides of diverse composition and electronic configuration, and thus tunable physical and chemical properties, for applications in hydrogen storage, thermal energy storage, ion conduction in electrochemical devices, and catalysis in fuel processing. The recent progress is reviewed here and strategic approaches for the design and optimization of complex hydrides for the abovementioned applications are highlighted.

In situ formed ultrafine NbTi nanocrystals from a NbTiC solid-solution MXene for hydrogen storage in MgH2

Abstract: A novel 2D layered NbTiC solid-solution MXene was synthesized from its MAX phase via a wet chemical etching process. While ball milling the NbTiC MXene with MgH2, ultrafine bimetal NbTi nanocrystals were formed in situ with a grain size of 5 nm, which offer highly stable catalytic activity for the hydrogen storage reaction of MgH2. The MgH2-9 wt% NbTiC sample starts releasing hydrogen from 195 °C, which is 80 °C lower than that for the additive-free sample. At 250 °C, it releases approximately 5.8 wt% H2 within 30 min, and the fully dehydrogenated sample takes up 4.0 wt% H2 within 15 min even at 50 °C under 50 bar H2 pressure. DFT calculations reveal a charge transfer process from Ti atoms to Nb atoms in the NbTi cluster and a lower absolute value of the adsorption energy of H2 on NbTi. This would presumably benefit both the breakage of Mg–H bonding and the detachment of H2 from the NbTi surface, and consequently lead to good catalytic activity.