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Smooth and dense preheated cerium (Ce) and manganese (Mn) codoped barium strontium titanate (CeMn-BST) films with various thicknesses have been prepared by improved sol-gel method. Capacitance-voltage curves show that with increasing film thickness, combination of dielectric properties are significantly improved with optimized values of about 1300 moderate permittivity, less than 0.007 dielectric loss, more than 58% tunability and hence near 180 figure of merit (FOM) for eight-layer CeMn-BST film. The objective of this paper is to study the improved mechanisms for such excellent dielectric properties. XRD shows that the films layered-grow mainly along (110) orientation and exhibit ABO3cubic perovskite structure. As film thickness increases, Ce3+and/or Mn2+ions are showing doping modes from donor doping to acceptor doping, the crystallization of films is enhancing, but the average grain sizes of the films show gradually decreased trend from about 45nm to 25nm in terms of the intensities of (110) diffraction peaks. AFM indicates that the films are getting smoother with smaller roughness with increasing thickness. XPS reveals that the films reveal decreased non-perovskite structure, element core levels and Fermi levels with increasing thickness. Leakage current densities are significantly decreased almost at two orders of magnitude with increasing thickness. Pure BST films are compared. [ABSTRACT FROM AUTHOR]

Manganese (Mn) and yttrium (Y) alternately doped Ba0.6Sr0.4TiO3(BST) films are novelly designed as MnBST/YBST/MnBST/YBST and prepared layer-after-layer on Pt wafer electrodes, and two films where one with the first layer preheated (1Mn/YBST) and the other with four layers preheated (4Mn/YBST) are focused on. XRD shows that two films grow along (110) orientation and reveal ABO3cubic perovskite structures and donor doping, but 4Mn/YBST film shows larger average grain size. SEM demonstrates that 1Mn/YBST film is composed of one 630nm-thick layer with nodular microstructure and the other 570nm-thick surface layer with columnar microstructure, whereas 4Mn/YBST film is 670 nm thick with nodular microstructure. AFM shows that two films are smooth with no cracks, but 4Mn/YBST film is denser with smaller roughness. Two films show more than 55% high tunabilities, but 4Mn/YBST film also reveals low losses of 0.0062∼0.0156 and high figure of merit (FOM) of near 90 at -35V and 100 kHz, fully meeting the needs of tunable microwave applications. [ABSTRACT FROM AUTHOR]

Cerium (Ce) and manganese (Mn) codoped Ba0.6Sr0.4TiO3(BST) films were prepared by improved sol-gel method and the effect of preheating on their dielectric properties was investigated. X-ray diffraction (XRD) reveals that the films grow principally along (110) orientations and show cubic perovskite structures. Preheating corresponds to smaller FWHMs, stronger crystallization and larger grain sizes, and preheating with codoping corresponds to the smallest FWHM, the strongest crystallization and the largest grain size. The prepared film can show tunability of 55.7%, dielectric loss of 0.0074∼0.0175 and approximately 75 FOM, meeting the needs of tunable microwave applications. [ABSTRACT FROM AUTHOR]

Abstract: Mn and Y alternately doped Ba0.6Sr0.4TiO3 film, denoted as Mn/Y-BST film, has been designed and prepared by improved sol–gel method, and the structure and dielectric properties of the film have been studied. Y or Mn doped BST film is also studied. X-ray diffraction reveals that all films grow along (110) orientation and show polycrystalline cubic perovskite structures, and Y3+ and Mn2+ ions enter into B-sites of ABO3 perovskite structure and substitute Ti4+ ions. The Mn/Y-BST film reveals better crystallization with larger crystal grain size. Atomic force microscopy and scanning electron microscopy confirm that the Mn/Y-BST film exhibits better crystallization. X-ray photoelectron spectroscopy shows that the Mn/Y-BST film presents less surface non-perovskite structure. Accordingly, the Mn/Y-BST film exhibits significantly nonlinear improvement in combination of dielectric properties. These results indicate that Mn/Y alternate doping is a novel route to excellent BST films for tunable microwave applications. [Copyright &y& Elsevier]

Abstract: Cerium and manganese codoped Ba0.6Sr0.4TiO3 (CeMn-BST) film and pure BST, Ce-BST and Mn-BST films were prepared. Influence of preheating on film crystallization and growing behavior was studied. X-ray diffraction (XRD) reveals that all films mainly grow along (110) orientation and show cubic ABO3 perovskite structures, and the preheating promotes Ce3+ and Mn4+ ions enter into B-sites and substitute Ti4+ ions. Preheating enhances crystallization and causes the strongest crystallization with CeMn-codoping. Atomic force microscopy (AFM) exhibits that films preheated show layered growth, while those not preheated show island growth, which are related to layer number and doping. Therefore, the films preheated show larger permittivities, higher tunabilities, and lower dielectric losses except the pure BST film and higher figures of merit (FOMs). Preheating with CeMn-codoping causes best dielectric properties with 56% tunability, 0.0037–0.0091 loss and near 150 FOM, meeting the needs of tunable microwave applications. [Copyright &y& Elsevier]

Presents a study that investigated the composition depth profiles, structure and ball-on-hard disk frictional characteristics of aluminum alloys 2024 plasma-based ion implanted with nitrogen, titanium and nitrogen then acetylene. Examination of the micro-hardness and nano-hardness of the layers; Observations on the graphitization phenomenon of a diamond-like carbon film; Discussion on the tribological morphology of sliding cycles dominated by rubbing and abrasive wear.

Abstract: Ba0.6Sr0.4TiO3 thin films were deposited on Pt/SiO2/Si substrate by radio frequency magnetron sputtering. High-resolution transmission electron microscopy (HRTEM) observation shows that there is a transition layer at BST/Pt interface, and the layer is about 7–8nm thickness. It is found that the transition layer was diminished to about 2–3nm thickness by reducing the initial RF sputtering power. X-ray photoelectron spectroscopy (XPS) depth profiles show that high Ti atomic concentration results in a thick interfacial transition layer. Moreover, the symmetry ν of ɛ r–V curve of BST thin film is enhanced from 52.37 to 95.98%. Meanwhile, the tunability, difference of negative and positive remanent polarization (P r), and that of coercive field (E C) are remarkably improved. [Copyright &y& Elsevier]

The development of Li-free anodes to inhibit Li dendrite formation and provide high energy density Li batteries is highly applauded. However, the lithiophobic interphase and heterogeneous Li deposition hindered the practical application. In this work, a 20 nm ultra-sleek high entropy alloy (HEA, NiCdCuInZn) tights loaded with HEA nanoparticles are developed by a thermodynamically driven phase transition method on the carbon fiber (HEA/C). Multiple Li + transport paths and abundant active sites are enabled by the cocktail effect of different constituent elements in HEA. These active sites with gradient absorption energies (-3.18 to -2.03 eV) facilitate selective binding, providing a low barrier for homogeneous Li nucleation. Simultaneously, multiple transport paths promote Li diffusion behavior with uniform Li deposition. Thus, the HEA/C achieves high reversibility of Li plating/stripping processes over 2000 cycles with a coulombic efficiency of 99.6% at 5 mA cm -2 /1 mAh cm -2 in asymmetric cells, as well as over 7200 h at 60 mA cm -2 /60 mAh cm -2 in symmetric cells. Moreover, the anode-free full cell with the HEA/C host has an average coulombic efficiency of 99.5% at 1 C after 160 cycles. This advanced HEA structure design shows a favorable potential application for anode-free Li metal batteries., (© 2023 Wiley-VCH GmbH.)

Thermally insulating aerogels can now be prepared from ceramics, polymers, carbon, and metals and composites between them. However, it is still a great challenge to make aerogels with high strength and excellent deformability. We propose a design concept of hard cores and flexible chains that alternately construct the aerogel skeleton structure. The approach gives the designed SiO 2 aerogel excellent compressive (fracture strain 83.32%), tensile. and shear deformabilities, corresponding to maximum strengths of 22.15, 1.18, and 1.45 MPa, respectively. Also, the SiO 2 aerogel can stably perform 100 load-unload cycles at a 70% large compression strain, demonstrating an excellent resilient compressibility. In addition, the low density of 0.226 g/cm 3 , the high porosity of 88.7%, and the average pore size of 45.36 nm effectively inhibit heat conduction and heat convection, giving the SiO 2 aerogel outstanding thermal insulation properties [0.02845 W/(m·K) at 25 °C and 0.04895 W/(m·K) at 300 °C], and the large number of hydrophobic groups itself also gives it excellent hydrophobicity and hydrophobic stability (hydrophobic angle of 158.4° and saturated mass moisture absorption rate of about 0.327%). The successful practice of this concept has provided different insights into the preparation of high-strength aerogels with high deformability.

In order to fundamentally suppress the shuttle effect, N 2 Plasma & Al 2 O 3 magnetron sputtered separators (Al 2 O 3 @N-PP) are proposed for lithium-sulfur batteries (LSBs). Such a dual-functional polysulfides (LiPSs) barrier separator greatly inhibits the shuttle effect from the perspective of physical and chemical interaction. Physically, the inherently electronegative amorphous Al 2 O 3 first achieves the repulsion of LiPSs to the sulfur cathode through the electrostatic repulsive effect, effectively preventing a large amount of soluble LiPSs from accumulating at the separator. At the same time, the Al 2 O 3 film seals the shuttle channel of LiPSs to a certain extent. Chemically, N 2 plasma-doped N heteroatoms form a lithium bond with Li + in LiPSs to achieve the first step chemical adsorption and anchoring of LiPSs. When the LiPSs reaches the amorphous Al 2 O 3 film, more stable chemical bonds are formed between Al 3+ and S 2- , Li + and O 2- to achieve more effective adsorption and anchoring of LiPSs. At 1C with a high sulfur loading up to 3-5 mg cm -2 the LSB contributes a specific charge capacity of 717.4 mAh g -1 , with high retention rate up to 75.49 % after 450 cycles. The U-shaped electrolytic cell experiment and ultraviolet-visible spectrum experiment confirmed the LiPSs barrier function of the functional separator., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Layered, Li-rich Mn-based oxides (LLMOs) are the most promising next-generation, high-energy batteries due to their relatively high specific capacities and high voltages. However, the practical application of LLMO cathodes is limited by low initial coulombic efficiencies (CEs) and poor cycling performance. Herein, we used the reaction of KMnO 4 and MnSO 4 under hydrothermal conditions to grow a nano-SCMO shell on the LLMO material surface (SCMO@LLMO). The unique particle/sheet compound structure of the SCMO shell is beneficial to the electrochemical reaction. SCMO has good Li storage characteristics and excellent surface structure stability in the single-crystal phase which further improves the reversible capacity, CE, and cyclic stability of the LLMO cathode. Therefore, the optimal coated sample (feedstock: 2 M KMnO 4 , SCMO@LLMO-2.0) exhibits a good initial discharge capacity (238.2 mA h g -1 at 1C and 173.8 mA h g -1 at 5C), initial CE (89.6% at 1C and 86.5% at 5C), and cycling performance (capacity retention of 84.67% at 1C and 62.72% at 5C after 200 cycles). This work adopts a hydrothermal method to synthesize a nano-single crystal composite material, laying a foundation for the preparation of the SCMO@LLMO cathodes for LLMO primary battery cathodes with high electrochemical performance., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Graphene has been combined with molybdenum disulfide (MoS 2 ) to ameliorate the poor cycling stability and rate performance of MoS 2 in lithium ion batteries, yet the underlying mechanisms remain less explored. Here, we develop multiscale modeling to investigate the enhanced electrochemical and thermal transport properties of graphene/MoS 2 heterostructures (GM-Hs) with a complex morphology. The calculated electronic structures demonstrate the greatly improved electrical conductivity of GM-Hs compared to MoS 2 . Increasing the graphene layers in GM-Hs not only improves the electrical conductivity but also stabilizes the intercalated Li atoms in GM-Hs. It is also found that GM-Hs with three graphene layers could achieve and maintain a high thermal conductivity of 85.5 W/(m·K) at a large temperature range (100-500 K), nearly 6 times that of pure MoS 2 [∼15 W/(m·K)], which may accelerate the heat conduction from electrodes to the ambient. Our quantitative findings may shed light on the enhanced battery performances of various graphene/transition-metal chalcogenide composites in energy storage devices.