Search

Solid oxide electrolysis cells (SOECs) have captured worldwide attention as a promising energy conversion device, but durability at large current densities is still an issue. Here, the authors present an encouraging stable anode design for electrolysis at high current densities, in which a nano La0.6Sr0.4CoO3−δ (LSC) catalyst network is integrated with robust microchannels of the yttria-stabilized zirconia scaffold. Such a controlled structured electrode not only allows rapid gas diffusion, but also provides sufficient active sites as well as firm anode–electrolyte interface adhesion for achieving highly stable and efficient electrolysis. These unique advantages lead to an extremely low polarization resistance of 0.010 Ω cm2 and high durability for over 100 h at a large current density of 3.4 A cm−2 at 800 °C. The outstanding performance demonstrates that the as-prepared cell structure may be generally applicable in the design of high-efficiency energy conversion systems. [ABSTRACT FROM AUTHOR]

NASICON‐type Na3VM(PO4)3 (M: transition metals) cathodes usually suffer from poor cycling stability in the voltage region of above 4 V versus Na+/Na owing to irreversible phase transition and severe structural distortion. Herein, the high entropy concept is extended to NASICONs and Na3VAl0.2Cr0.2Fe0.2In0.2Ga0.2(PO4)3 (NVMP) with high purity is obtained. The NVMP achieves a highly reversible specific capacity of 102 mAh g−1 (2.5–4.4 V vs Na+/Na) via the successive redox reaction of V3+/V4+/V5+ together with a long‐term lifespan of 5000 cycles at 20 C (a capacity retention of 86.8%). Even at an extreme temperature of −20 °C, the NVMP cathode can still provide excellent cycling performance (a capacity retention of 94.2% at 5 C after 1000 cycles). Moreover, the increased configurational entropy in the electrode renders a quite small cell volume change of 1.1%. The sodium ion storage mechanism containing solid solution‐type in the voltage range of 2.5–3.8 V and bi‐phasic in 3.8–4.4 V is revealed by ex situ XRD analysis. Pairing with a hard carbon anode, NVMP//HC cell offers a specific capacity of 81 mAh g−1 at 0.2 C based on the cathode mass. This high‐entropy engineering is expected to be widely applicable for the development of polyanionic electrode materials. [ABSTRACT FROM AUTHOR]

The planetary gearbox transmission system in wind turbines has complex structures and generally operates under non-stationary conditions. Thus its measured responses are of high complexity and nonlinearity, which brings a great challenge in the development of reliable condition monitoring techniques for the planetary gearbox transmission system. As a prevalent and effective tool for analyzing the non-stationary vibration signal with strong nonlinearity, the Vold–Kalman filtration technique has excellent capabilities of tracking the targeted harmonic components of vibrations, which can significantly benefit planetary gearbox fault diagnostics. However, the tracking accuracy is heavily enslaved to the selection of the rational bandwidth for the Vold–Kalman filter. An inappropriate bandwidth could impair the characteristics of the targeted harmonic responses, and as a consequence, the monitoring process becomes no longer reliable. To address this issue, a novel bandwidth selection methodology for the Vold–Kalman filter is developed in this paper. Through comprehensively depicting the targeted harmonic response using features in multiple domains, the rational bandwidth can be selected for Vold–Kalman filtering, and then, a reliable monitoring process can be ensured. Additionally, a tacho-less speed estimation procedure is utilized in this paper to acquire the instantaneous rotational speed from the vibration signal directly. With the rational bandwidth and the estimated rotational speed, the desired harmonic components of vibrations can be adaptively extracted and tracked through the Vold–Kalman filter with high accuracy, and at the same time, the irrelevant or unwanted components are excluded completely. The effectiveness and superiority of the proposed adaptive Vold–Kalman filtration for wind turbine planetary gearbox diagnostics are demonstrated and validated experimentally. [ABSTRACT FROM AUTHOR]

Four MOFs with mixed ligands, [Zn3(3-BABA)2(bpa)2(H2O)2]n (1), [Cd3(3-BABA)2(bpa)2]n (2), [Cd3(3-BABA)2(bpe)2]n (3), and {[Cd3(3-BABA)2(bib)(DMA)2]·H2O}n (4) (where 3-H3BABA = 4′,4′′′-(((2-carboxyphenyl)azanediyl)bis(methylene))bis(([1,1′-biphenyl]-2-carboxylic acid)), bpa = 4,4′-azopyridine, bpe = 1,2-bis(pyridin-4-yl)ethane, and bib = 1,4-bis(imidazole)butane), have been synthesized. They are characterized by single crystal X-ray diffraction, X-ray powder diffraction (XRPD), thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy. In 1, two 3-BABA and two bpa bridge three Zn2+ ions to form a bicyclic [Zn3(3-BABA)2(bpa)2] unit which is further bridged by carboxylate groups with its adjacent units, resulting in a one-dimensional chain. In 2, 3 and 4, the [Cd3(CO2)6] units are bridged by six 3-BABA ligands into a three-dimensional structure. However, the adjacent [Cd3(CO2)6] units in 2 and 3 are doubly-bridged simultaneously by corresponding pyridyl ligands, while the adjacent [Cd3(CO2)6] units in 4 are singly-bridged simultaneously by corresponding pyridyl ligands. The luminescence sensing investigation indicates that compound 1 exhibits extremely sensitive and selective detection of Cu2+ with a detection limit of 0.363 μM, and compounds 2–4 show extremely sensitive and selective detection of Fe3+ with detection limits of 0.539 μM, 0.265 μM, and 0.748 μM, respectively. Competitive experiments in the presence of interfering cations with 1–4 revealed no major change in the quenching efficiency. [ABSTRACT FROM AUTHOR]