All solid-state electrochromic window of electrodeposited WO3 and prussian blue film with PVC gel electrolyte

An all-solid-state electrochromic window (SEW) of prussian blue and electrodeposited WO₃ film with poly(vinyl chloride) PVC gel electrolyte with high conductivity (2 mS/cm) at room temperature has been fabricated. The SEW has been found to be excellent for electrochromism and memory characteristics. W 4f core level of WO₃ film as a function of the injected charge has been investigated using X-ray photoelectron spectroscopy (XPS). W 4f peaks become broader after coloration.     

Electrochemical behaviour of erbium in the eutectic LiCl-KCl at W and Al electrodes

The electrochemical behaviour of Er(III) was studied in the molten LiCl-KCl eutectic for temperatures ranging from 653 to 823 K. Transient electrochemical techniques, such as cyclic voltammetry, chronopotentiometry and chronoamperometry were used in order to study the reaction mechanism and the transport parameters of electroactive species at a tungsten electrode. The results showed that in the eutectic LiCl-KCl, the reduction of Er(III) occurs in a step with a global exchange of three electrons, and that electrocrystallization plays an important role in the electrodeposition process. Chronoamperometric studies indicated instantaneous nucleation of erbium with three-dimensional growth of the nuclei whatever the applied overpotential.Mass transport towards the electrode is a simple diffusion process, and the temperature dependence of the diffusion coefficient of the electroactive specie Er(III) was written in the following equation:

     

Inhibition of Whisker Growth on the Surface of Sn-3Ag-0.5Cu-0.5Ce Solder Alloyed with Zn

Solder alloys doped with rare-earth elements have been reported to show many beneficial effects. However, tin whiskers have been observed to appear on the surface of Sn-3Ag-0.5Cu-0.5Ce solder joints after air exposure for short periods. Such a phenomenon of abnormal whisker growth may significantly degrade the reliability of electronic packaging. The present study shows that the tin whiskers can be prevented by the addition of 0.5 wt.% Zn into a Sn-3Ag-0.5Cu-0.5Ce solder. The inhibition effect on the whisker growth is correlated to the refining of (Ce_0.9Zn_0.1)Sn₃ intermetallics in this Sn-3Ag-0.5Cu-0.5Ce-0.5Zn alloy.     

Electrochemistry of thulium on inert electrodes and electrochemical formation of a Tm–Al alloy from molten chlorides

The electrochemical behaviour of TmCl₃ solutions was studied in the eutectic LiCl–KCl in the temperature range 673–823 K using inert and reactive electrodes, i.e. W and Al, respectively.On an inert electrode, Tm(III) ions are reduced to metallic thulium through two consecutive steps:

Tm(III) + 1e ↔ Tm(II) and Tm(II) + 2e ↔ Tm(0)

The electroreduction of Tm(III) to Tm(II) was found to be quasi-reversible. The intrinsic rate constant of charge transfer, k⁰, as well as of the charge transfer coefficient, α, have been calculated by simulation of the cyclic voltammograms and logarithmic analysis of the convoluted curves. Electrocrystallization of thulium plays an important role in the electrodeposition process, being the nucleation mode affected by temperature.The diffusion coefficients of Tm(III) and Tm(II) ions have been found to be equal. The validity of the Arrhenius law was verified by plotting the variation of the logarithm of the diffusion coefficients vs. 1/T.The electrode reactions of Tm(III) solutions at an Al electrode were also investigated. The results showed that for the extraction of thulium from molten chlorides, the use of a reactive electrode made of aluminium leading to Al–Tm alloys seems to be a pertinent route.Potentiometric titrations of Tm(III) solutions with oxide donors, using a ytria stabilized zirconia electrode “YSZE” as a pO²⁻ indicator electrode, have shown the formation of thulium oxychloride and thulium oxide and their corresponding solubility products have been determined at 723 K (pk_s(TmOCl) = 8.0 ± 0.3 pk_s(Tm₂O₃) = 18.8 ± 0.7).     

吹脱法处理稀土硫氨废水试验研究

针对高氨氮、高硬度,较难处理的稀土硫氨废水,采用吹脱法进行了脱氨试验研究。通过单因素试验得出：在pH=12、吹脱温度T=30℃、吹脱时间t=3h的条件下,氯铵废水氨氮含量可由10383.8mg/L降低到316mg/L,去除率可达96.9%。     

The effect of rare-earth oxides on the energy storage performances in BaTiO3 based ceramics

In this work, 0.7BaTiO₃-0.3Sr_0.2Bi_0.7TiO₃ (0.7BT-0.3SBT) ceramics with 0.15 mol% various rare-earth oxides doped are designed and synthesized by the conventional solid-state route. All prepared samples exhibited a single perovskite phase and dense microstructure with fine grain size (0.2–0.5 μm) after sintering at 1180 °C. Especially, the Gd-doped 0.7BT-0.3SBT ceramics exhibited excellent energy storage performances; the corresponding recoverable energy density and efficiency were 3.2 J/cm³ and 91.5% under an electric field of 330 kV/cm, respectively. Meanwhile, doping with Gd caused the BT-based ceramics to possess excellent temperature (30–150 °C) and outstanding frequency stabilities (10–1000 Hz). Moreover, the pulsed charge-discharge experiments revealed that a high power density of 59 MW/cm³ and a fast discharge speed of 110 ns with outstanding temperature stability could be synchronously obtained in the Gd-doped composition. All these features are attractive for pulsed power applications.     

Emergence of relaxor behavior along with enhancement in energy storage performance in light rare-earth doped Ba0.90Ca0.10Ti0.90Zr0.10O3 ceramics

Nano-sized light rare-earth (La, Pr, Nd, and Sm) doped Ba_0.90Ca_0.10Ti_0.90Zr_0.10O₃ ceramics were synthesized to enhance the energy storage performance. The Rietveld study of bare and doped samples has shown tetragonal crystal symmetry and a single-phase perovskite structure. The rare-earth addition in Ba_0.90Ca_0.10Ti_0.90Zr_0.10O₃ has resulted in a remarkable change in the microstructure of the doped samples. The addition of Nd in Ba_0.90Ca_0.10Ti_0.90Zr_0.10O₃ lattice has resulted in optimum grain size and density among the five compositions. As a result of improvement in morphological characteristics in the Nd-doped sample, the dielectric, ferroelectric and piezoelectric characteristics were significantly enhanced. The Nd-doped sample has shown a relaxor behavior with a maximum dielectric constant of 10788 combined with a high saturation polarization of 41.88 μC/cm². Further, the material has shown optimum electromechanical behavior with excellent aging characteristics. The obtained properties of Nd-doped Ba_0.90Ca_0.10Ti_0.90Zr_0.10O₃ sample justifies its potential application in multi-layer energy storage capacitors.     

Enhanced upconversion study of Er3+-Yb3+ codoped NaYF4 phosphors synthesized by the reverse microemulsion method

Herein, nanocrystals of Er³⁺ and Er³⁺, Yb³⁺ co-doped NaYF₄ upconversion (UC) phosphor were prepared via the reverse-microemulsion method. The impact of different concentrations of Er³⁺ ions on the UC emission intensity after 980?nm diode laser excitation is discussed. The structure, morphology and composition of the nanophosphors were confirmed by X-ray diffraction, transmission electron microscopy, scanning electron microscopy and the results showed the presence of NaYF₄ nanocrystals with hexagonal phases of NaYF₄. The UC spectra revealed two emission bands including a green and a red emission band and the CIE coordinate for the samples were estimated. The present research revealed that the reverse-microemulsion approach will be suitable for the synthesis of efficient upconversion nanophosphors.     

Effect of Sm on the cyclic stability of La–Y–Ni-based alloys and their comparison with RE–Mg–Ni-based hydrogen storage alloy

The LaY₂Ni_9.7Mn_0.5Al_0.3 and LaSm_0.3Y_1.7Ni_9.7Mn_0.5Al_0.3 alloys have been synthesized to investigate the effect of Sm partial substitution for Y on the cyclic stability of A₂B₇-type La–Y–Ni-based alloys. Their cyclic properties were also compared with the A₂B₇-type (RE_0.85Mg_0.15)₂(NiAl)₇ (RE = Rare Earth) alloys. The gas-solid and electrochemical cycle lives were tested. The structural stability, pulverization, and oxidation/corrosion performances were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical methods. The partial substitution of Sm for Y improves anti-corrosion and anti-pulverization performances, thereby increasing the cycle life of A₂B₇-type La–Y–Ni-based hydrogen storage alloys. The A₂B₇-type RE–Y–Ni-based alloys exhibit better crystal structure stability, but the gas-solid and electrochemical cyclic stability is worse than A₂B₇-type (RE_0.85Mg_0.15)₂(NiAl)₇ alloys due to easier pulverization of particles and the oxidation of Y elements.