Xiaozhou Cao

Deep eutectic solvents (DESs) were considered as a potential electrolyte because of their low price, harmless to environment and wider electrochemical window potential compared to water. In this work, Fe(III)/Fe(II) and Zn(II)/Zn redox couples were used as the positive and negative active materials, respectively, in a DES system using choline chloride and ethylene glycol in a molar ratio of 1 : 2 (ethaline). The possible working mechanism of the battery was studied by cyclic voltammetry, spectroscopic and simulation methods. The effects of different temperatures, concentrations of zinc ions in the anolyte and current densities on battery performance were evaluated. The results showed that the designed zinc‐iron battery should preferably be operated at a current density of 0.5 mA cm⁻² and the temperature of 313~323 K, which will improve the energy efficiency and maintain a high coulombic efficiency. The variation of cycle performance test presents a different pattern from the usual batteries, which is due to the effect of RO⁻ group. At 313 K and 0.5 mA cm⁻², the coulombic efficiency increases from 14.1 % to 100.2 % after 46 cycles, and then remains at about 100 % during the rest 54 cycles, which demonstrates a good cycle stability of DES‐based zinc‐iron battery.

Deep eutectic solvent (DES) has been widely used in the field of metal electrodeposition as an economical and environmentally friendly green solvent. Metallic bismuth films were prepared by electrodeposition from choline chloride-malonic acid (ChCl-MA) deep eutectic solvent (DES) containing BiCl₃. Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy were used to study the structure of ChCl-MA-BiCl₃, and the results showed that Bi(III) was in the form of [BiCl₆]³⁻ ions. The viscosity of ChCl-MA-BiCl₃ ranges from 200 to 1200 mPa·s at temperatures from 363 K to 323 K. The conductivity of 0.01 M Bi(III) in ChCl–MA is 3.24 ms·cm⁻¹ at 363 K. The electrochemical behavior and electrodeposition of Bi(III) in DES were investigated by cyclic voltammetry (CV) and chronoamperometry. The results showed that the electrodeposition reaction was a quasi-reversible reaction controlled by the diffusion and the nucleation of bismuth was a three-dimensional instantaneous nucleation. The diffusion coefficient of Bi(III) in ChCl-MA was 1.84 × 10⁻⁹ cm²·s⁻¹. The electrodeposition product was observed by scanning electron microscopy (SEM), and the results showed that the deposition potential has a significant influence on the morphology of the bismuth film. X-ray photoelectron spectroscopy (XPS) shows that bismuth and bismuth oxides are present in the deposited film obtained by electrodeposition.

Although experimental results of preparing AlB12 by self-propagating high-temperature synthesis using Mg-B2O3-Al2O3 as raw material has been studied, the theoretical calculations for the preparation of AlB12 have not been examined as thoroughly. In this article, for the first time, we report on the study of theoretical calculation and the adiabatic temperature, calculated, and compared with the actual reaction temperature. The Gibbs free energy for each level of reaction is also calculated. The calculation results show that the adiabatic temperature is 2789.5 K, the standard Gibbs free energy of each reaction is less than 0, and the reaction can proceed spontaneously, which is consistent with the results of the experiment.

Compared with conventional aqueous and ionic liquid electrolytes, deep eutectic solvent (DES) are considered as electrolyte for redox flow batteries because they have a wider electrochemical window and relatively low price. In this study, Ce^IV/Ce^III and Zn^II/Zn redox couples are used as the positive and negative active materials, respectively, in an electrolyte consisting of choline chloride ethylene glycol (ethaline). The structure of Ce^III in the positive electrolyte is inferred through spectrum detection. Ce^IV/Ce^III and Zn^II/Zn redox couples show a stable potential difference of 2.2 V (vs. Ag) through cyclic voltammetry. The charge and discharge performance of battery was tested at different current densities. In addition, battery performance was evaluated at different temperatures and concentrations of cerium in the electrolyte. Consequently, at a current density of 0.5 mA cm⁻² at room temperature and using 1.0 m Ce^III, the battery performance reaches the best coulombic efficiency of 84 %.

The electrochemical behavior and electrodeposition of Sn were investigated in choline chloride (ChCl)–urea deep eutectic solvents (DESs) containing SnCl₂ by cyclic voltammetry (CV) and chronoamperometry techniques. The electrodeposition of Sn(II) was a quasi-reversible, single-step two-electron-transfer process. The average transfer coefficient and diffusion coefficient of 0.2 M Sn(II) in ChCl–urea at 323 K were 0.29 and 1.35 × 10⁻⁹ cm²∙s⁻¹. The nucleation overpotential decreased with the increase in temperature and SnCl₂ concentration. The results of the chronoamperometry indicated that the Sn deposition on tungsten electrode occurred by three-dimensional instantaneous nucleation and diffusion controlled growth using the Scharifker–Hills model. Scanning electron microscopy (SEM) showed that the morphology of the deposits is uniform, as a dense and compact film prepared by potentiostatic electrolysis on Cu substrate. X-ray diffraction (XRD) analysis revealed that the deposits were pure metallic Sn.

V–4Cr–4Ti alloys exhibit important advantages as a candidate structural materials for fusion reactor first-walls and blanket applications. V–4Cr–4Ti alloys were prepared by direct electrochemical reduction of the solid mixture of V₂O₃, Cr₂O₃ and TiO₂ in the molten CaCl₂–NaCl eutectic at 1073 K. The influence of cell voltage, sintering temperature and electrolysis time on the electrolysis process are reported. The microstructure and phase compositions of the products were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) during the electrolysis process. The results showed that V–4Cr–4Ti alloys can be obtained at the voltage of 3.1 V and the time of 0.5 h. Cr₂O₃ was first reduced to Cr metal, while V₂O₃ and TiO₂ was reduced to low-valence oxide of vanadium and titanium. The reduction rate increases with increasing cell voltage, with much perovskite oxide formed during the electrolysis process.

The effect of Ti addition on the residual Al content and mechanical properties of B₄C-Al composites fabricated by vacuum infiltration was investigated in the present study. The B₄C-Al composite materials were fabricated using [Ti+B₄C] preforms preheated at 1700ºC for 1 h and Al alloys infiltrated in vacuum atmosphere at 1100ºC for 2 h. The phase composition indicated that TiB₂ has high wettability to Al as a result of the preheating. SEM and EDX results revealed a number of Al dimples are on the fracture surface due to the existence of TiB₂. When the content of added Ti increases to 30%, the [Ti+B₄C] preform is characterized by a minimal porosity (33.11%) and a maximal density, a corresponding amount of residual Al of 33.11% and a minimal fracture toughness (5.03 MPa·m^1/2) with a hardness of up to 63 HRC. The residual Al and the mechanical properties of the composite material preform were determined by the Ti content of the preform.

In this paper, we studied the effect of Ti addition on the microstructure and fracture toughness of Boron nitride- Aluminum (BN-Al) composite materials that were synthesized by vacuum infiltration. The BN-Al composite materials were fabricated by preheating the [Ti+BN] preforms at 1700º for 1 hour before Al alloys were infiltrated into the preforms in a vacuum atmosphere at 1100º for 2 hours. X-ray diffraction (XRD) patterns showed that the diffraction peaks of titanium diboride (TiB₂) appeared when the [Ti+BN] preforms were preheated. It is thought that metal Al protected are visible and this could be achieved by the generation of TiB₂ when Al infiltrated into the preform from fractography. The matching fracture toughness of the [Ti+BN] preforms gradually improve when Ti content was increased.