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Aqueous zinc-ion batteries offer the greatest promise as an alternative technology for low-cost and high-safety energy storage. However, the development of high-performance cathode materials and their compatibility with aqueous electrolytes are major obstacles to their practical applications. Herein, we report the synthesis of orthorhombic V2O5·nH2O nanorods as cathodes for aqueous zinc batteries. As a result, the electrode delivers a reversible capacity as high as 320 mAh g−1 at 1.0 A g−1 and long-term cycling stability in a wide window of 0.2 to 1.8 V using a mild ZnSO4 aqueous electrolyte. The superior performance can be attributed to the improved stability of materials, inhibited electrolyte decomposition and facilitated charge transfer kinetics of such materials for aqueous zinc storage. Furthermore, a full cell using microsized Zn powder as an anode within capacity-balancing design exhibits high capacity and stable cycling performance, proving the feasibility of these materials for practical application. [ABSTRACT FROM AUTHOR]

[Display omitted] Aqueous rechargeable batteries offer a safe alternative for electrochemical energy storage, integrating cost-efficiency and energy density to meet the demand for stationary applications. Recent efforts have focused on the improvement of electrode materials in aqueous electrolytes, particularly the cycle life and energy reliability of batteries. The anion intercalation chemistry in graphite could be an alternative cathode candidate, often requiring an upper cut-off potential above 4.5 V vs. Li+/Li. Such a potential readily exceeds the electrochemical stability windows of water-based electrolytes. Herein, we provide a progress report and critical comment on the reversible intercalation chemistry in graphite compounds, i.e. , anion and halogen intercalations, for the development of economical, high-energy aqueous rechargeable batteries. In addition, this review focuses on the charge carrier species, their charge storage mechanisms and battery configurations, aiming to provide solutions to solve the remaining key challenges for aqueous batteries. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study on the failure mechanism of high-current gallium arsenide photoconductive semiconductor switches (GaAs PCSSs) triggered by the laser diode. We propose a Blumlein pulse forming line to test the GaAs PCSS. The result shows that the damage of GaAs PCSS almost occurs at the anode under the circumstances that either anode or cathode is illuminated, since the highest amplitude of Gunn oscillation always occurs on the anode. We speculate that the failure of high-current GaAs PCSS is attributed to the Gunn effect according to the statistics about failure factors of GaAs PCSS. We use a scanning electron microscope to semiquantitatively analyze the compositions of the erosions microball or granules, which are gallium and arsenium. The result proves our speculation. [ABSTRACT FROM AUTHOR]

A B-dot was used for measuring cathode emission current in the injector of a linear induction electron accelerator. The measured current waveforms in commissioning were different from our initial expectation. This could well be explained by that the measured current waveform was the sum of actual emission current and displacement current. The displacement current could be derived by the measured diode voltage and the calculated diode capacitance. The actual emission current waveform was then obtained by subtracting the displacement current from the measured waveform. The pure displacement current waveform was also measured by the B-dot, while there was no emission from a thermionic cathode. The calculated and measured displacement current waveforms were well consistent with each other. The B-dot’s sensitivity factor calibrated by comparing the aforementioned two waveforms was equal to our theoretical estimate within an error range. The obvious displacement current may also exist in the similar pulsed power facilities, which contain high-voltage and fast pulses. It can be processed by the same methods discussed in this paper. [ABSTRACT FROM PUBLISHER]

Abstract: A novel network LiFePO4/C composite was prepared by mixing precursor solution with carbon aerogel (CA) via a simple solution impregnation method, characterized by XRD, SEM, EDS and electrochemical analysis. The results revealed that the LiFePO4 nanowire forming on the ektexine of CA intertwined with LiFePO4/CA particles and formed a special web structure. The initial discharge capacity was improved to be 139.3 mAh g−1 at 10 C and the capacity retention is near 100% after 50 cycles. The web structure could improve electron transport and electrochemical activity effectively. [Copyright &y& Elsevier]

[Display omitted] • The tunnel-type Ti-substituted Na 0.44 MnO 2 was investigated as cathode for aqueous zinc batteries. • The Ti-substitution can efficiently improve the electrochemical kinetics with superior high-rate capability and cycling stability. • The facilitated reaction mechanism with stepwise Zn2+ and H+ insertions was versified. • The optimal Na 0.44 Mn 0.78 Ti 0.22 O 2 material exhibits a high reversible capacity and a cycling life record for 2400 cycles. The tunnel-type sodium manganese oxide (Na 0.44 MnO 2) materials are considered as promising cathode candidates for rechargeable batteries due to their low cost and sustainability. However, the direct implementation in aqueous batteries, as an emerging energy storage technology, was not fully realized in terms of the reversibility and long-cycling stability. Herein, the tunnel-type Ti-substituted Na 0.44 MnO 2 (NMTO) is investigated as a cathode material for aqueous zinc-metal batteries. It is identified that the Ti-substitution has a significant effect on improving its rate capability and cycling stability. As a result, the optimal Na 0.44 Mn 0.78 Ti 0.22 O 2 (NMTO-0.22) material exhibits a reversible capacity of 109.6 mAh/g at 1.0 A g−1, and 71% of the initial capacity can be retained after 2400 cycles. Such performance can be attributed to the enhanced insertion mechanisms in the tunnel structure, as verified by the post-mortem spectroscopic and microscopic techniques. Density functional theory (DFT) calculations enclose that the average charge density in Mn 3d orbits near the Fermi level and Mn participation in redox reaction are improved after Ti-substitution, supporting the facilitated electrochemical kinetics of NMTO. This work demonstrates that the Ti-substituted Na 0.44 MnO 2 is a promising cathode material for aqueous zinc-metal batteries, and provides a fundamental understanding on the charge storage mechanisms. [ABSTRACT FROM AUTHOR]

Abstract: Using different gas source, four types of diamond thin films were prepared on silicon substrate by microwave plasma chemical vapor deposition (MPCVD) technology, and characterized in detail through scanning electron microscopy (SEM), Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. High-current pulsed emission characteristics, tested with a 2MeV line-inducing injector, showed that all of CVD diamond films had high emission current density (>70A/cm2) and [100] textured B-doped microcrystalline diamond film possessed the largest emission current density of 115.1A/cm2. No obvious bright light and luminescent zones from side view CCD images indicated a possible pure field-emission mechanism of these diamond cathodes. Simultaneously, large decrease in the electron emission capability, above 15%, could be observed after several pulsed measurements, but this decrease could be completely recovered through the treatment of surface re-hydrogenation for emitted diamond cathodes, suggesting that emission performance of CVD diamond cathodes was closely relevant to hydrogen coverage ratio. The present data indicated that as-deposited CVD diamond films could be a potential candidate as cold cathode for the application in high-current electron emission field. [Copyright &y& Elsevier]