Lithium-based Electrolyte Research Articles

Penetration of lithium into ASR-affected concrete due to electro-osmosis of lithium carbonate solution

An electrochemical technique to accelerate the penetration of the lithium ions (Li+), contained within a lithium-based electrolyte solution, into concrete has been developed for the purpose of suppressing ASR-induced expansion. From the results of past research work, it has appeared that the penetration depth of Li+ is limited to the outer concrete surface and that it is difficult to make Li+ penetrate into the deeper part of the concrete. In this study, an experimental investigation was carried out with the aim of understanding the influence of varying lithium salts and the temperature of the electrolyte solution on the migration properties of ions in concrete and their effect on ASR-induced expansion of concrete. The electrochemical migration of Li+ was found to accelerate when using a Li2CO3 electrolyte solution and with increasing temperature, with concentrations of Li+ after treatment resulting in the decreased expansion rate of concrete following such treatment.

The improving electrochromic performance of nickel oxide film using aqueous N,N-dimethylaminoethanol solution

New nickel oxide thin films with a micro-scale thickness and porous structure were fabricated using a sol–gel method in a mixed solvent containing N,N-dimethylaminoethanol (dmaeH) and distilled water at a 1:1 ratio. After annealing, the deposited film transformed to a well oriented, porous nickel oxide thin film. This nickel oxide thin film showed enhanced charge capacity and greater optical transmittance changes in a lithium-based electrolyte, and may be applied to WO3/Li+-based electrolyte/NiO electrochromic devices requiring long cycles.

Effect of Electrochemical Penetration of Lithium Ions on Concrete Expansion Due to ASR

Concrete expansion due to alkali-silica reaction (ASR) is one of the serious deterioration mechanisms of concrete structures. However, no promising repair method for ASR has been established yet. In a bid to remedy this situation, an electrochemical technique to accelerate the penetration of the lithium ions (Li+) in a lithium-based electrolyte solution into concrete has been developed for the purpose of suppressing ASR-induced expansion due to Li+. From the results of past research work, the penetration area of Li+ is limited around the concrete surface and it is difficult to make Li+ penetrate into the deeper part of concrete.In this study, experimental investigation was carried out aiming to grasp the influence of the kinds of lithium salts and the temperature of the electrolyte solution on the migration properties of ions in concrete and ASR-induced expansion of concrete. The electrochemical migration of Li+ was found to accelerate with rises in temperature and the effective diffusion coefficient of Li+ increased three times with changes in temperature from 20°C to 40°C in the case of a Li2CO3 electrolyte solution. Moreover, ASR-induced expansion of concrete after this treatment was suppressed compared with the case of non-treated specimens.

Improved electrochromical properties of sol–gel WO 3 thin films by doping gold nanocrystals

In this investigation, the effect of gold nanocrystals on the electrochromical properties of sol–gel Au doped WO 3 thin films has been studied. The Au–WO 3 thin films were dip-coated on both glass and indium tin oxide coated conducting glass substrates with various gold concentrations of 0, 3.2 and 6.4 mol%. Optical properties of the samples were studied by UV–visible spectrophotometry in a range of 300–1100 nm. The optical density spectra of the films showed the formation of gold nanoparticles in the films. The optical bandgap energy of Au–WO 3 films decreased with increasing the Au concentration. Crystalline structure of the doped films was investigated by X-ray diffractometry, which indicated formation of gold nanocrystals in amorphous WO 3 thin films. X-ray photoelectron spectroscopy (XPS) was used to study the surface chemical composition of the samples. XPS analysis indicated the presence of gold in metallic state and the formation of stoichiometric WO 3. The electrochromic properties of the Au–WO 3 samples were also characterized using lithium-based electrolyte. It was found that doping of Au nanocrystals in WO 3 thin films improved the coloration time of the layer. In addition, it was shown that variation of Au concentration led to color change in the colored state of the Au–WO 3 thin films.

Synthesis and electrochromic study of sol–gel cuprous oxide nanoparticles accumulated on silica thin film

In this study, electrochromic properties of cuprous oxide nanoparticles, self-accumulated on the surface of a sol–gel silica thin film, have been investigated by using UV–visible spectrophotometry in a lithium-based electrolyte cell. The cuprous oxide nanoparticles showed a reversible electrochromic process with a thin film transmission reduction of about 50% in a narrow wavelength range of 400–500 nm, as compared to the bleached state of the film. Using optical transmission measurement, we have found that the band gap energy of the films reduced from 2.7 eV for Cu 2O to 1.3 eV for CuO by increasing the annealing temperature from 220 to 300 °C in an N 2 environment for 1 h. Study of the band gaps of the as-deposited, colored and bleached states of the nanoparticles showed that the electrochromic process corresponded to a reversible red–ox conversion of Cu 2O to CuO on the film surface, in addition to the reversible red–ox reaction of the Cu 2O film. X-ray photoelectron spectroscopy indicated that the copper oxide nanoparticles accumulated on the film surface, after annealing the samples at 200 °C. Surface morphology of the films and particle size of the surface copper oxides have also been studied by atomic force microscopy analysis. The copper oxide nanoparticles with average size of about 100 nm increased the surface area ratio and surface roughness of the silica films from 2.2% and 0.8 nm to 51% and 21 nm, respectively.

Influence of Coloring Voltage and Thickness on Electrochromical Properties of e-beam Evaporated WO3 Thin Films

In this investigation, the effect of coloring voltage and thickness on optical and also electrochromical properties of thin films has been studied. The thin films were grown on glass and indium tin oxide coated conducting glass substrates by e-beam evaporation at different thicknesses of 200, 400, and . Optical properties of the deposited samples were characterized in the ultraviolet-visible range . The optical bandgap energy of the was obtained in a range of showing its increase by decreasing the film thickness. The refractive index of the films was measured around 2 in the visible range. Surface chemical states of the films were studied by X-ray photoelectron spectroscopy, which showed the stoichiometry of our deposited tungsten oxide thin films is acceptable. Atomic force microscopy was used for studying surface morphology of the deposited films. The electrochromic properties of the films were characterized using a lithium-based electrolyte. It was shown that there is an optimum coloring voltage for each film thickness, which maximizes the change in optical density during electrochromic process. The coloration efficiency of the samples at the optimum voltage was linearly improved by increasing the film thickness at a constant wavelength .

Characteristics of e-beam deposited electrochromic CeO 2 thin films

Cerium oxide (CeO 2) thin films were deposited by e-beam PVD on various substrates, such as glass, ITO-coated glass, Si wafers and fused silica. Substrate temperature was kept constant at 125 °C for all samples. The technological parameters of interest were oxygen partial pressure and plasma assistance during the deposition process. The basic structural properties of these films were studied by XRD, transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Composition of the samples was evaluated by X-ray photoelectron spectroscopy (XPS) and infrared transmittance (FTIR). The samples were optically characterized in the Ultraviolet–visible (UV–VIS) range (190–900 nm). The electrochromic properties of CeO 2 were characterized using a lithium-based electrolyte. This paper assesses the feasibility of using pure CeO 2 thin films as ion-storage layers in all-solid inorganic electrochromic devices.