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Magnesium hydrides are promising solid-state hydrogen storage materials due to their high gravimetric hydrogen storage density and low cost. However, the high temperature, slow kinetics, and poor cycle stability hinder the practical application of magnesium hydrides as hydrogen storage materials. Here, amorphous TiO2 was embedded into MgH2 particles as hydrogen conveying channels by atomic layer deposition followed by a ball-milling process to improve their hydrogen adsorption and desorption kinetics. The MgH2 particles embedded with amorphous TiO2 were then wrapped by graphene nanosheets (MgH2–20 nm TiO2@Gra) to enhance their cycle stability. The onset hydrogen desorption temperature of MgH2–20 nm TiO2@Gra has been reduced to 199 °C, which is about 100 °C lower than that of pristine MgH2 (290 °C). MgH2–20 nm TiO2@Gra has been demonstrated to rapidly release 6.04 wt% H2 at 275 °C in 10 min, where only 0.086 wt% H2 was released from pristine MgH2 at 300 °C in 10 min. MgH2–20 nm TiO2@Gra has been found to absorb 5.39 wt% H2 at a temperature as low as 50 °C (30 bar H2), where only 1.67 wt% H2 was absorbed by pristine dehydrogenated MgH2 at 200 °C in 20 min. Moreover, MgH2–20 nm TiO2@Gra has been demonstrated to still release 5.92 wt% of H2 after 50 cycles with a capacity retention of 95.5%. The multivalent Ti+ and abundant oxygen defects have been measured during different de/rehydrogenation states to explore the effects of amorphous TiO2 as hydrogen conveying channels. The amorphous TiO2 hydrogen channels with graphene wrappers have been demonstrated to be an effective strategy to enhance the hydrogen storage properties and cycle stability of MgH2, which is applicable for various solid-state hydrogen storage materials. [ABSTRACT FROM AUTHOR]

Microplasma at atmospheric pressure has been widely used in many fields due to the lower power consumption, higher plasma density, as well as better uniformity and stability. In this work, the microplasma characteristics of direct current atmospheric pressure glow discharge, including discharge morphology and electrical properties have been investigated with various interelectrode gaps (10–600 μ m) and discharge currents (1–6 mA), and simultaneously, a finite element simulation has been conducted to obtain the distribution of the electric field and particle density. The evolution of cathode layer, anode layer and Faraday dark space at this scale was captured with a higher spatial resolution (∼1 μ m) for the first time, demonstrating that the cathode layer, especially the cathode sheath rather than the positive column, plays a dominant role in the transition of the microplasma. As the gap shrinks to a size less than cathode layer (∼40 μ m), the cathode sheath with a high electric field is compressed, leading to a rapid decrease of the discharge voltage. The discharge voltage remains basically unchanged regardless of the discharge current, because the electric field in the cathode sheath is limited by the accumulated space charge. The experimental results are well verified and explained by the simulation results. This study provides an in-depth understanding of the glow discharge mechanism at microscale, and of the stability of glow discharge at atmospheric pressure, and benefits to future research on the atmospheric pressure large-area microplasma and its related application. [ABSTRACT FROM AUTHOR]

Due to the intrinsic safety and cost effectiveness, aqueous Zn‐ion batteries (AZIBs) are considered a promising candidate for future energy storage systems. However, the widespread implementation of AZIBs faces significant obstacles due to various undesirable side reactions, including hydrogen evolution reaction (HER), corrosion, and uncontrolled dendrite growth at the anodes. Here, 4‐hydroxybenzoic acid sodium salt (PHB) is employed in the ZnSO4 electrolyte to enable highly‐reversible zinc anodes. PHB has a greater tendency to bind with the Zn surface, resulting in increased steric effects within the electrolyte. As a result, it hinders the direct interaction between anode and water while facilitating the uniform plating of Zn2+. Zn/Zn batteries with PHB additives realized more than 1600 h stable cycling life under 1 mA cm−2 and 1 mAh cm−2. Moreover, Zn/Cu batteries with PHB additives achieved a reversible plating/stripping process for over 500 cycles with high average CE of 98.6 %. In addition, the assembled Zn/NH4V4O10 batteries with PHB additive yielded 80.5 mAh g−1 after 1000 cycles at 10 A g−1. The inexpensive and effective application of PHB as an electrolyte additive has the potential to significantly enhance the stability and dependability of ZIBs. [ABSTRACT FROM AUTHOR]

Although doubly fed induction generators (DFIG) are widely used, difficulties in early fault detection and severity assessment for inter-turn short-circuit (ITSC) faults are highly prominent. In this manuscript, a novel incipient fault detection and state assessment method based on external leakage flux sensing and modified multiscale poincare plots (MMSPP) is proposed. An external leakage flux sensor is placed on the axial-end position of the generator to monitor the presence and evolution of ITSC faults. Multiscale poincare mapping is a novel nonlinear tool that is further developed and modified using the normal cumulative distribution function and multiscale computing methods to capture the behavior evolution and changes in the generator's external leakage flux signals. The healthy indicator is based on the analysis of elliptical orbit features extracted from MMSPP, established by support vector data description with parameter optimization. The effectiveness of the proposed method was implemented and verified under an experimental environment on a 100 kW DFIG platform to detect incipient inter-turn short circuits (mainly considering the two-turn ITSC) and evaluate the performance degradation (three- to eight-turn ITSC) with 0%, 50%, and 100% different load conditions. The experimental results showed the viability of the approach and fault indicator for incipient fault detection and condition assessment of the wind generator's low inter-turn insulation faults and for relative quantification of ITSC fault severity. [ABSTRACT FROM AUTHOR]

Uncontrollable side reactions and dendrites severely undermine the stability and reversibility of Zn anodes and remain significant challenges for aqueous zinc-ion batteries (AZIBs). Herein, it is demonstrated that glutamine (Gln) is a multifunctional electrolyte additive to enable highly stable and reversible Zn anodes. Theoretical and experimental results reveal that Gln has three functions: preferentially absorbing on the Zn anode and constructing a water-poor interface, enhancing the steric effect, and optimizing the solvation structures of Zn2+. Consequently, Zn//Zn batteries exhibited an impressive cycling durability and high cumulative capacity at 3 mA cm−2. Furthermore, Zn//Cu batteries also demonstrated a remarkably reversible stripping/deposition process accompanied by a notably high average coulombic efficiency of 99.6%. In addition, the fabricated Zn//NH4V4O10 batteries with Gln also yielded impressive cycle performances and capacity retention. Gln exhibits promising attributes as a cost-effective and versatile electrolyte additive to facilitate the stability and reversibility of AZIBs. [ABSTRACT FROM AUTHOR]

First-principles calculations were performed to analyze the atomic structures and electrochemical energy storage properties of novel MoS2⊥boridene heterostructures by anchoring MoS2 nanoflakes on Mo4/3B2 and Mo4/3B2O2 monolayers. Both thermodynamic and thermal stabilities of each heterostructure were thoroughly evaluated from the obtained binding energies and through first-principles molecular dynamics simulations at room temperature, confirming the high formability of the heterostructures. The electrochemical properties of MoS2⊥Mo4/3B2 and MoS2⊥Mo4/3B2O2 heterostructures were investigated for their potential use as anodes for alkaline metal ion batteries (Li+, Na+ and K+). It was revealed that Li+ and Na+ can form multiple stable full adsorption layers on both heterostructures, while K+ forms only a single full adsorption layer. The presence of a negative electron cloud (NEC) contributes to the stabilization of a multi-layer adsorption mechanism. For all investigated alkaline metal ions, the predicted ion diffusion dynamics are relatively sluggish for the adsorbates in the first full adsorption layer on MoS2⊥boridene heterostructures due the relatively large migration energies (>0.50 eV), compared to those of second or third full adsorption layers (<0.30 eV). MoS2⊥Mo4/3B2O2 exhibited higher onset and mean open circuit voltages as anodes for alkaline metal-ion batteries than MoS2⊥Mo4/3B2 hybrids because of enhanced interactions between the adsorbate and the Mo4/3B2O2 monolayer with the presence of O-terminations. Tailoring the size and horizontal spacing between two neighboring MoS2 nano-flakes in heterostructures led to high theoretical capacities for LIBs (531 mA h g−1), SIBs (300 mA h g−1) and PIBs (131 mA h g−1) in the current study. [ABSTRACT FROM AUTHOR]

Surface discharge inception voltage (SDIV) with epoxy silicon carbide nanocomposite material in [LN.sub.2] medium is about three times higher than that in air. Under AC voltage that SDIV increases with increase in wt% of silicon carbide (SIC) material in epoxy nanocomposites. Dielectric measurements indicates an increase in temperature of the specimen and the weight percentage of SIC filler in epoxy resin increases the permittivity of the material. Also, irrespective of percentage of SiC in epoxy resin, the tan([delta]) reduces with increase in frequency and the converse at room temperature. The UHF signal measured during surface discharge activity in air/[LN.sub.2] medium has frequency content in the range of 0.5-1.5 GHz. The charge decay characteristics of epoxy SiC nanocomposites indicate the deposited charge is less and the charge decay time reduces with increase in wt% of SiC in epoxy resin. The surface roughness caused due to surface discharge activity is high under negative DC voltage compared with positive DC/AC voltage. The phase resolved partial discharge (PRPD) analysis indicates discharges occur at the near peak of the AC voltage on inception of surface discharge and at higher stress it appears at the rising portion of AC voltage., INTRODUCTION Bulk power transmission with reduced transmission and distribution power loss is a major challenge to power engineers. The worldwide researchers are trying to transmit bulk power with reduced power [...]