In the active material of a lithium-ion secondary battery, electrons and lithium-ions react at the same time. The fact that the active material can transfer electrons with a small reaction ...overvoltage leads to a reduction in the internal resistance of the battery. Therefore, when the electrical resistance was measured by changing the electrode material in contact with the active material, it was found that the electrical resistance of the active material was reduced depend on the carbon materials make contact with the active material.
An experimental investigation is conducted to develop an electrohydrodynamic (EHD) pump based on microelectromechanical systems technology. In EHD conduction pumping, Coulomb force is the main ...driving force for fluid motion. The nonequilibrium process of the dissociation and recombination of dielectric liquid, HFE-7100, produces heterocharge layers in the vicinity of the electrodes. The attraction between the heterocharge layers and electrode surfaces generates the net motion in the dielectric liquid by applying asymmetric electric fields. In order to generate the asymmetric electric fields, three electrode patterns were prepared. The working fluid was confined between two electrodes facing each other. The generated pressure was measured for the different asymmetric electric fields. Also, the effect of deviation between the upper and lower electrode patterns on the pressure was investigated. Finally, the liquid flow rate, power consumption, and pump efficiency were measured with an optimized electrode arrangement. It is clear from the experimental results that, in addition to the conduction pumping, the ion injection generated at the microelectrode edge increases the pressure.
We have compared the electrochemical properties of LiMn2O4 nanoparticle and microparticle electrode without binder and conductive additives. The rate performance of the spinel LiMn2O4 is improved ...with decreasing the size of primary particles, which have been observed by cross-sectional LV-SEM. From the ESR measurements, g-factor has been obtained as 2.0, indicating that the electrons in conduction band of active material act as a charge carrier to enhance the high-rate CV performance.
The effects of various moisture contents (ranging from 50 to 2500 ppm) in a dielectric liquid on electrohydrodynamic (EHD) pumping have been investigated. The static pressure and the flow rate ...induced by the EHD pump were examined using dibutyl sebacate (DBS) as the working fluid. One of the additives in DBS was deionized water. It was found that the pressure head induced by the EHD pump was significantly sensitive to different moisture contents. A simple predictive model was derived using the Coulomb force and a linear dielectric increment approximation. This model predicted that the static pressure increases linearly in line with the greater moisture contents due to the high dielectric constant of deionized water. It was observed that the pressure, as a function of moisture content, behaves in a similar manner.
The hole carrier mobility of deposited thin film composed of 4,4′-BisN-(1-naphthyl)-N-phenylamino-biphenyl (NPD) was measured using the dark injection (DI) method. The mobility basically agreed with ...that measured by the time-of-flight method. We also evaluated the effect of a hole injection barrier on the estimated mobility, using several surface treatments of indium–tin oxide anode.
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► The hole mobility of organic thin film was measured using the dark injection method. ► An improved bridge circuit achieved faster response time. ► The mobility agreed with that measured by the time-of-flight method.
The hole carrier mobility of deposited thin film composed of 4,4′-BisN-(1-naphthyl)-N-phenylamino-biphenyl (NPD) was measured using the dark injection method. An improved bridge circuit achieved faster response time, which enabled the evaluation of practical hole transporting material with high hole mobility, using thin vacuum deposited film. The mobility basically agreed with that measured by the time-of-flight method. We also evaluated the effect of a hole injection barrier on the estimated mobility, using several surface treatments of indium–tin oxide anode. The results indicated that increasing barrier height decreases the estimated mobility; however, its effect was relatively small.
In this study the formula for expressing contact resistance Rc between the aluminum (Al) current collector and positive electrode composite in lithium secondary batteries is derived as follows: (1) ...Rc is proportional to the thickness of the Al oxide film and apparent electric susceptibility of the composite χe. (2) Rc decreases when the active material is coated with Carbon Nanotubes (CNT) due to the reduction of χe. (3) χe can be formulated by the contribution ratio Ci of the component i of the composite, with Ci determined by the dispersed condition of the composite.
A new flow-injection/anodic stripping voltammetry has been demonstrated to assess ultra-trace mercury(II) using track-etched microporous membrane electrodes. The electrodes were prepared by the ...sputtering of gold or platinum onto both sides of a membrane filter with a smooth flat surface and with cylindrical pores having uniform diameter. The deposition of mercury from a mercury(II) solution was performed while the sample solution flowed through the membrane electrodes. After the deposition step, an anodic stripping voltammogram was obtained by sweeping the potential from 0 to +0.8 V vs. Ag/AgCl. In this case, the sample solution flowed through the pores of the 10-μm-thick membrane filters. Efficient electrolysis occurred during passage of the sample solution through the electrode, of which the pore size was 0.4 μm. In this study, the voltammetry described above was demonstrated using an FIA system. The continuous-flow mode showed a detection limit of 0.04 μg L−1 when the experimental conditions of the flow rate and the deposition time were set at 0.5 mL min−1 and 180 s. In the sample-injection mode equipped with a 1-mL sample loop, a linear relation was found for 0.5 – 4.0 μg L−1 of a mercury(II) standard solution (r = 0.995). The detection limit was 0.05 μg L−1. This method was applied to the ultra-trace determination of mercury(II) in river-water samples.
The study on the formation of lithium alloying with Bi thin layer electrode and its kinetics was carried out in 1
mol/dm
3 LiClO
4/PC electrolyte. In situ XRD and chronopotentiometry results ...confirmed the formation of LiBi and Li
3Bi alloy phases with the open circuit potentials of 0.830 and 0.805
V, respectively. The formation of Li
3Bi alloy rather than LiBi alloy was found to be responsible for the mechanical degradation of Li–Bi alloy electrode. Lithium diffusion coefficient in LiBi alloy was evaluated to be in the order of 10
−13
cm
2/s by ac impedance measurement. This smaller lithium diffusion coefficient in thin layer electrode than that in the common sheet electrode was attributed to the intrinsic properties of the thin layer electrode. Furthermore, a mechanism involving the adsorption process at the electrode surface was proposed for lithium alloying with bismuth.
In this paper, an evaluation method for measuring contact resistance of aluminum current collector surfaces in energy storage systems was established. Contact resistance was calculated by a ...combination of chronopotentiometry and AC impedance method. Also, we found that contact resistance is dependent on current density.
In the active material of a lithium-ion secondary battery, electrons and lithium-ions react at the same time. The fact that the active material can transfer electrons with a small reaction ...overvoltage leads to a reduction in the internal resistance of the battery. Therefore, when the electrical resistance was measured by changing the electrode material in contact with the active material, it was found that the electrical resistance of the active material was reduced depend on the carbon materials make contact with the active material.
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