Turning bulk materials into 0D, 1D and 2D metallic nanomaterials by selective aqueous corrosion

Recent Development in Nanoconfined Hydrides for Energy Storage

Hydrogen is the ultimate vector for a carbon-free, sustainable green-energy. While being the most promising candidate to serve this purpose, hydrogen inherits a series of characteristics making it particularly difficult to handle, store, transport and use in a safe manner. The researchers' attention has thus shifted to storing hydrogen in its more manageable forms: the light metal hydrides and related derivatives (ammonia-borane, tetrahydridoborates/borohydrides, tetrahydridoaluminates/alanates or reactive hydride composites). Even then, the thermodynamic and kinetic behavior faces either too high energy barriers or sluggish kinetics (or both), and an efficient tool to overcome these issues is through nanoconfinement. Nanoconfined energy storage materials are the current state-of-the-art approach regarding hydrogen storage field, and the current review aims to summarize the most recent progress in this intriguing field. The latest reviews concerning H2 production and storage are discussed, and the shift from bulk to nanomaterials is described in the context of physical and chemical aspects of nanoconfinement effects in the obtained nanocomposites. The types of hosts used for hydrogen materials are divided in classes of substances, the mean of hydride inclusion in said hosts and the classes of hydrogen storage materials are presented with their most recent trends and future prospects.

Carbon Nanotube Films for Energy Applications

This perspective article describes the application opportunities of carbon nanotube (CNT) films for the energy sector. Up to date progress in this regard is illustrated with representative examples of a wide range of energy management and transformation studies employing CNT ensembles. Firstly, this paper features an overview of how such macroscopic networks from nanocarbon can be produced. Then, the capabilities for their application in specific energy-related scenarios are described. Among the highlighted cases are conductive coatings, charge storage devices, thermal interface materials, and actuators. The selected examples demonstrate how electrical, thermal, radiant, and mechanical energy can be converted from one form to another using such formulations based on CNTs. The article is concluded with a future outlook, which anticipates the next steps which the research community will take to bring these concepts closer to implementation.

Activity-Tuning of Supported Co-Ni Nanocatalysts via Composition and Morphology for Hydrogen Storage in MgH2

Developing cheap metal nanocatalysts with controllable catalytic activity is one of the critical challenges for improving hydrogen storage in magnesium (Mg). Here, it is shown that the activity of graphene-anchored Co-Ni nanocatalysts can be regulated effectively by tuning their composition and morphology, which results in significantly improved hydrogen storage in Mg. The catalytic activity of supported Co-Ni nanocatalysts is demonstrated to be highly dependent on their morphology and composition. When Ni was partly substituted by Co, the shape of these nanocatalysts was changed from spherical to plate-like, thus corresponding to a decrease in activity. These alterations intrinsically result in enhanced hydrogen storage properties of MgH₂, i.e., not only does it exhibit a decreased peak desorption temperature but also a positive change in the initial activation for sorption. The results obtained provide a deep understanding of the tuning of catalytic activity via composition and morphology and further provide insights into improving hydrogen storage in Mg-based materials.

Synergistic effects of Gd and Co on the phase evolution mechanism and electrochemical performances of Ce2Ni7-type La-Mg-Ni-based alloys

The influences of Gd and Co co-substitution for La and Ni on phase structures, and electrochemical properties of La_0.83-xGd_xMg_0.17Ni_3.35-2xCo_2xAl_0.15 (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.

Uniform gallium oxyhydroxide nanorod anodes with superior lithium-ion storage

Exploration of a novel metal oxyhydroxide material provides potential candidates for lithium ion battery (LIB) anodes. In the present work, uniform GaOOH nanorods have been successfully synthesized via a simple hydrothermal method and employed as an anode material for LIBs for the first time. The obtained GaOOH nanorods show a high-purity phase with an average length of ∼1.4 μm and a width of ∼100 nm. As an anode, it delivers a stable capacity of ∼1089 mA h g^-1 at a 0.5 A g^-1 current density upon 300 cycles and a high rate capacity of ∼639 mA h g^-1 at 2 A g^-1, where the pseudocapacitance plays a dominant role with a capacity contribution ratio of about 83% at 2.0 mV s^-1. This enhanced storage performance can be attributed to a 1D nanostructure with efficient electron and ion transfer as well as strain relaxation upon multiple-cycling.