Top-gate field-effect transistor based on monolayer WS2 with an ion-gel gate dielectric

A top-gate field-effect transistor (FET), based on monolayer (ML) tungsten disulfide (WS2), and with an ion-gel dielectric was developed. The high electrical contact resistance of the Schottky contacts at the n-type transition metal dichalcogenides/metal electrode interfaces often adversely affects the device performance. We report the contact resistance and Schottky barrier height of an FET with Au electrodes. The FET is based on ML WS2 that was synthesised using chemical vapour deposition and was assessed using the transfer-length method and low-temperature measurements. Raman and photoluminescence spectra were recorded to determine the optical properties of the WS2 layers. The ML WS2 FET with an ion-gel top gate dielectric exhibits n-type behaviour, with a mobility, on/off ratio of 1.97 cm2/V·s, 1.51×105, respectively.

Suppressing electrolyte-lithium metal reactivity via Li+-desolvation in uniform nano-porous separator

Lithium reactivity with electrolytes leads to their continuous consumption and dendrite growth, which constitute major obstacles to harnessing the tremendous energy of lithium-metal anode in a reversible manner. Considerable attention has been focused on inhibiting dendrite via interface and electrolyte engineering, while admitting electrolyte-lithium metal reactivity as a thermodynamic inevitability. Here, we report the effective suppression of such reactivity through a nano-porous separator. Calculation assisted by diversified characterizations reveals that the separator partially desolvates Li+ in confinement created by its uniform nanopores, and deactivates solvents for electrochemical reduction before Li0-deposition occurs. The consequence of such deactivation is realizing dendrite-free lithium-metal electrode, which even retaining its metallic lustre after long-term cycling in both Li-symmetric cell and high-voltage Li-metal battery with LiNi0.6Mn0.2Co0.2O2 as cathode. The discovery that a nano-structured separator alters both bulk and interfacial behaviors of electrolytes points us toward a new direction to harness lithium-metal as the most promising anode.

The Coupling between Voltage Profiles and Mechanical Deformations in LAGP Solid Electrolyte During Li Plating and Stripping

Chemo-mechanical degradation at the solid electrolyte – Li metal electrode interface is a bottleneck to improve cycle life of all-solid state Li-metal batteries. In this study, in operando digital image correlation (DIC) measurements provided temporal and spatial resolution of the chemo-mechanical deformations in LAGP solid electrolyte during the symmetrical cell cycling. The increase in strains in the interphase layer was correlated with the overpotential. The sudden increase in strains coincides with the mechanical fracture in LAGP detected by Micro CT. This work highlights the mechanical deformations in LAGP / Li interface and its coupling with the electrochemical behavior of the battery.

Influence of assembly procesS condition of A gantry crane on the corrosion resistance of welds

The article presents an analysis of the manufacturing process of gantry crane elements in the unit production regime. Gantry cranes are one of the most important heavy-duty mechanical components designed for lifting and loading heavy and bulky loads. In the analyzed case, the assembly of large-size elements in the form of a welding process was carried out outside. Therefore, there was a problem with the corrosion resistance of the elements produced in this way. In this article, special attention is paid to the performance of welded joints of such large elements and their disadvantages related to the conditions of the assembly process. These joints were made on the basis of typical, low-carbon structural steel (grade S355J2, steel with the number 1.0562) and Nickel alloy (Alloy 59, X2CrNiMoCuN22-5-3, steel with the number 2.4605) using the metal electrode. The weldability of investigated joints was assessed. The aim of the article is to analyze the influence of assembly conditions and subsequent corrosion protection of joints on their corrosion resistance under operating conditions. Appropriate tests have been carried out for this purpose. The tests showed the negative influence of external conditions on the corrosion resistance of the entire gantry crane structure.

Model Electrochemical Biosensor for the Detection of Methanol in Aqueous Solutions with Yeast Cells

An electrochemical device that serves as a model biosensor and contains yeast Saccharomyces cerevisiae as the active biological element was developed. Different configurations of the electrochemical cells were assembled and tested. Stainless steel was used in the electrochemical cell composition process and the surface of this metal electrode was modified with a thin layer of WO3 if necessary. The yeast Saccharomyces cerevisiae was adhered to the working electrode. The resulting model biosensor was then used to monitor the response to a 10% CH3OH. For detection of biological activity, the electrochemical impedance spectroscopy (EIS) method was applied with a portable potentiostat/galvanostat, where the Bode and the Nyquist plots were interpreted. The stability of the device was beforehand determined by measuring the open circuit potential (OCP). The topography of the electrodes was inspected using the techniques of scanning electron microscopy and optical microscopy. The investigated model biosensor as a case study for the development of more complex biosensors that utilize living cells as the active layer.

The Stable 3D Zn Electrode for High-Power Density Zn Metal Batteries

A stable Zn metal electrode can develop rechargeable zinc metal batteries (RZMBs) which have the high theoretical capacity (820 mAh/g), low redox potential, and intrinsic safety. However, the corrosion of Zn metal in aqueous electrolytes and Zn dendrite formation during the plating process leads to poor cycling and thus hinders the development of RZMBs. Here, we employed ionic liquid-based gel polymer (poly(vinylidene fluoride)-co-hexafluoropropylene, PVDF-HFP) and acetylene black (AB) to achieve a stable and flexible three-dimensional (3D) Zn/AB/PVDF-HFP film electrode with ionic and electronic conductive networks and high surface area, showing 26 times higher plating/stripping current than planar Zn plate. By developing a continuous structure between the ionic liquid-based gel polymer membrane and the flexible 3D Zn/AB/PVDF-HFP electrode, the low resistance, high rate capability and long cycle life (> 800 h) was obtained. Our work shows a flexible Zn film electrode and ionic liquid-based gel polymer electrolyte, could pave the path for rechargeable and high-cycle life thin-film RZMBs.