All-solid-state sodium batteries (ASSSBs) are promising candidates for grid-scale energy storage. However, there are no commercialized ASSSBs yet, in part due to the lack of a low-cost, simple-to-fabricate solid electrolyte (SE) with electrochemical stability towards Na metal. In this work, we report a family of oxysulfide glass SEs (Na
Sodium lignosulfonate -chitosan (SLS-CS) polyelectrolyte complex was prepared by alkaline lignin and chitosan as raw materials. The structure and thermal stability of SLS-CS polyelectrolyte were characterized by FTIR, XRD, DSC. The results indicated that NH 3+ was formed by the protonated amino groups of chitosan and then came into SLS-CS polyelectrolyte complex with -SO3Na of sodium lignosulfonate through electrostatic adsorption. Compared with the sodium lignosulfonate and chitosan, the thermal decomposition temperature of SLS-CS raised and thus improved the thermal stability; the amorphous peak tends to decrease; SLS-CS polymer arrangement appeared more ordering, and the molecular interaction were enhanced.
A novel flexible P/carbon nanofibers@graphene electrode, which exhibits an excellent electrochemical performance, is fabricated via a vapor-redistribution and electrospinning method.
Abstract Carbon materials are used as the anode materials of potassium‐ion batteries (KIBs) thanks to the feasible intercalation of potassium ions. However, their rate capability and cycling performance are still unsatisfactory. In this work, FeCl 3 ‐intercalated expanded graphite (FeCl 3 ‐EG) is first reported as an excellent anode material of KIBs. Attributed to the unique structure with FeCl 3 sandwiched between the adjacent graphene layers, the FeCl 3 ‐EG electrode delivers a high reversible capacity of 269.5 mAh g −1 at 50 mA g −1 and 133.1 mAh g −1 at an ultrahigh current density of 5000 mA g −1 . The FeCl 3 ‐EG electrode also exhibits an ultrastable cycling performance. Even after 500 cycles at the current density of 50 mA g −1 , the FeCl 3 ‐EG electrode can still deliver a discharge capacity of 224.1 mAh g −1 with a high capacity retention of ≈88.82%. Moreover, the FeCl 3 ‐EG electrode is measured at an ultrahigh current density of 2000 mA g −1 for 1300 cycles, with a high capacity retention of ≈70.38%. Ex situ X‐ray diffraction, Raman, and high‐resolution transmission electron microscopy measurements are performed to investigate the potassium storage mechanism of FeCl 3 ‐EG electrode, which confirms the FeCl 3 ‐EG a promising anode material for high‐performance KIBs.
Two-dimensional (2D) van der Waals (vdW) heterostructures offer new platforms for exploring novel physics and diverse applications ranging from electronics and photonics to optoelectronics at the nanoscale. The studies to date have largely focused on transition-metal dichalcogenides (TMDCs) based samples prepared by mechanical exfoliation method, therefore it is of significant interests to study high-quality vdW heterostructures using novel materials prepared by a versatile method. Here, we report a two-step vapor phase growth process for the creation of high-quality vdW heterostructures based on perovskites and TMDCs, such as 2D Cs3Bi2I9/MoSe2, with a large lattice mismatch. Supported by experimental and theoretical investigations, we discover that the Cs3Bi2I9/MoSe2 vdW heterostructure possesses hybrid band alignments consisting of type-I and type-II heterojunctions because of the existence of defect energy levels in Cs3Bi2I9. More importantly, we demonstrate that the type-II heterojunction in the Cs3Bi2I9/MoSe2 vdW heterostructure not only shows a higher interlayer exciton density, but also exhibits a longer interlayer exciton lifetime than traditional 2D TMDCs based type-II heterostructures. We attribute this phenomenon to the reduced overlap of electron and hole wavefunctions caused by the large lattice mismatch. Our work demonstrates that it is possible to directly grow high-quality vdW heterostructures based on entirely different materials which provide promising platforms for exploring novel physics and cutting-edge applications, such as optoelectronics, valleytronics, and high-temperature superfluidity.
According to integration design concept of forced air convection cooling system aerodynamic design of small axial-flow 9238 fan for the CPU is implemented.File of 3D curves which are produced from Fortran procedure are imported into Pro/E to build solid modeling.The performance curve of fan prototype which is fabricated by CNC is measured in a standard wind tunnel.To reduce costs and shorten the design time,CFD is carried out to predict the performance of fan.According to outflow angle of fan series of radial heat sinks are developed.Based on the hexahedral block-grid strategy the numerical simulation is carried out on systems of fan and streamlined heat sink with Multiple Rotating Reference Frame and RNG k-e Model.Results show that resistance of the streamlined heat sink reduces by 15.9%when compared to the traditional heat sink.The numerical simulation proves to be true by the experiment.Series of heat sinks can reach the aim of high thermal exchange effect under the direction of the integration design concept.
All-solid-state lithium metal batteries are projected to offer one of the highest specific energy among rechargeable batteries, positioning them as a front-runner for electric vehicle applications. Lithium metal anodes outperform conventional graphite anodes in terms of cell-level energy density. However, maintaining a conformal metal–electrolyte contact is a great challenge. The volumetric change of the lithium metal anode during stripping produces voids, which deteriorates the Li–electrolyte contact. To address this challenge, β-phase Li solid solution (i.e., Li-Mg alloy) has been shown to exhibit improved contact with the solid electrolyte during stripping. Moreover, Li solid solution has a similar electrochemical potential as Li, making it a potential replacement for Li metal anodes without sacrificing cell-level energy density. In this study, we show that the chemical properties of the alloy play an essential role in the morphological stability of metal–solid electrolyte interface. We compare the stripping behavior of pure Li and Li-Mg alloy anodes in argyrodite electrolyte and characterize the morphological evolution of the interface using operando scanning electron microscopy (SEM). We also analyze the electro-chemo-mechanical properties of Li and Li alloy anodes during stripping with galvanostatic electrochemical impedance spectroscopy (GEIS) to compare the influence of composition change and interfacial void on the electrode overpotential and interface resistance. Our research visualizes the morphological and compositional evolution of alloy metal anode during stripping and rationalizes their improved interfacial stability against solid electrolytes. Acknowledgment: This work was supported by the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy (EERE) under the Vehicle Technologies Program under Contract DE-EE0008864. Figure 1
The rich morphology of 2D materials grown through chemical vapor deposition (CVD), is a distinctive feature. However, understanding the complex growth of 2D crystals under practical CVD conditions remains a challenge due to various intertwined factors. Real-time monitoring is crucial to providing essential data and enabling the use of advanced tools like machine learning for unraveling these complexities. In this study, we present a custom-built miniaturized CVD system capable of observing and recording 2D MoS2 crystal growth in real time. Image processing converts the real-time footage into digital data, and machine learning algorithms (ML) unveil the significant factors influencing growth. The machine learning model successfully predicts CVD growth parameters for synthesizing ultralarge monolayer MoS2 crystals. It also demonstrates the potential to reverse engineer CVD growth parameters by analyzing the as-grown 2D crystal morphology. This interdisciplinary approach can be integrated to enhance our understanding of controlled 2D crystal synthesis through CVD.
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