• Journal of Electrochemical Science and Technology
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• v.14 no.3
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• pp.262-271
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• 2023

For electrode stability and the electrochemical performance of the Li-ion cell, it is essential that the active ingredients and unique additives in the polymer binder be well dispersed with the solvent-based slurry. The efficient procedure used to create the slurry affects the rheological characteristics of the electrode slurry. When successively adding different steps of Nmethyl-2-pyrrolidone (NMP) solvent to the cathode composition, it is evenly disseminated. The electrochemical performance of the Li-ion cells and the electrodes made with slurry formed by single step and multiple steps of addition of NMP solvent are examined. To preform rheological properties of cathode electrode slurry on Ni-rich Lithium Nickel-Cobalt-Aluminum Oxide (LiNi_0.80Co_0.15Al_0.05) (NCA). Also, we investigate different step addition of electrode formation and mechanical strength characterization like peel strength. According to the EIS study, a multi-step electrode slurry has lower internal resistance than a single-step electrode slurry, which results in better electrical characteristics and efficiency. Further, microstructure of electrodes is obtained electrochemical performance in the 18650 cylindrical cells with targeted capacity of 1.5 Ah. The slurry of electrodes prepared by single step and multiple steps of addition of NMP solvent and its effect on the fabrication of 1.5 Ah cells. A three-step solvent addition on slurry has been found to be a lower internal resistance than a single-step electrode slurry as confirmed by the EIS analysis, yielding improved electrical properties and efficiency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.671-674
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• 2004

This paper presents design and analysis of multi-layered ring-dot type piezoelectric transformer. These transformers are useful for step up and step down. The transformers consist of disk type multi-layered piezoelectric ceramic plates. The finite element method(FEM) was used for analysis transformer. Vibration mode, electric field and equivalent elastic strain of piezoelectric transformer were simulated by changing frequency. As results, the strain was distributed in isolation part entirely. We can get the operated in step up transformer when the inner side electrode using by input parts. Also we can get the step down transformers using by input Part as outer side electrode. The step up ratio and step down ratio was increased by decreasing inner side electrode. The resonance frequency was increased by increasing inner side electrode when the transformer was operated in step down transformer. But the step up one was decreased. From these results, we can expect to multi-layered ring-dot type piezo transformers as step up and step down transformers.

• Korean Journal of Materials Research
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• v.28 no.4
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• pp.235-240
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• 2018

We propose a speedy two-step deposit process to form an Au electrode on hole transport layer(HTL) without any damage using a general thermal evaporator in a perovskite solar cell(PSC). An Au electrode with a thickness of 70 nm was prepared with one-step and two-step processes using a general thermal evaporator with a 30 cm source-substrate distance and $6.0{\times}10^{-6}$ torr vacuum. The one-step process deposits the Au film with the desirable thickness through a source power of 60 and 100 W at a time. The two-step process deposits a 7 nm-thick buffer layer with source power of 60, 70, and 80 W, and then deposits the remaining film thickness at higher source power of 80, 90, and 100 W. The photovoltaic properties and microstructure of these PSC devices with a glass/FTO/$TiO_2$/perovskite/HTL/Au electrode were measured by a solar simulator and field emission scanning electron microscope. The one-step process showed a low depo-temperature of $88.5^{\circ}C$ with a long deposition time of 90 minutes at 60 W. It showed a high depo-temperature of $135.4^{\circ}C$ with a short deposition time of 8 minutes at 100 W. All the samples showed an ECE lower than 2.8 % due to damage on the HTL. The two-step process offered an ECE higher than 6.25 % without HTL damage through a deposition temperature lower than $88^{\circ}C$ and a short deposition time within 20 minutes in general. Therefore, the proposed two-step process is favorable to produce an Au electrode layer for the PSC device with a general thermal evaporator.

• Journal of the Semiconductor & Display Technology
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• v.8 no.4
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• pp.89-94
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• 2009

The influence on a stability of thermal plasma has been investigated in an electrode structure of non-transferred plasma torch. The variations of dynamic characteristic of the arc voltage was analyzed and compared in terms of voltage character and nozzle types for both the step-shaped nozzles and magnetic-approved cylindrical nozzle. From the experimental results, an electrode gap, flow rate of arc gas, and currents are considered as major operational parameters. As conclusion, it was assured that a torch with step-shaped nozzles of magnetic-approved type produce the stable plasma jet.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.6
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• pp.81-86
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• 2012

This paper describes the analysis technique of risk voltage around grounding electrode by new touch and step voltage measurement methods. We have analyzed three techniques for risk voltage measurement, such as footprint-electrode method, test-probe method, and simulated-personnel method. We have selected test-probe method considering applicability of site. In order to reduce error related to the location of the auxiliary electrode, we propose a new approach to perform risk voltage measurement with minimum errors and short auxiliary electrode distances. Field tests were carried out at a grounding grid. It can be concluded that the proposed method will be satisfactory for risk voltage measurement.

• Journal of the Semiconductor & Display Technology
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• v.9 no.3
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• pp.5-9
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• 2010

Recently, the important issues of solar cell are low cost and high efficiency. Making low cost and high efficiency solar cell, there are many effects to development of inexpensive wafer, simplify process and improve optical, electrical properties. In this the study, the 2 step texturing method using micro blaster was developed to decrease reflection of incident lights. Air bridge electrode structure is suggested to expand the effective surface area and decrease the series resistance of finger electrode. The effects of 1 step texturing and 2 step texturing by micro blaster are compared. Reflectance of 1 step and 2 step texturing are measured 28.7% and 25.5%, respectively. The reflectance of 2 step texturing sample is lower about 3.2% than 1 step textured sample.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.2
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• pp.171-177
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• 2004

Voltage step-down characteristics in Ring/Dot type piezoelectric transformer were examined as a function of the area of input electrode when the area of output electrode is fixed. The effects of driving frequency and load resistance on the voltage step-down characteristics were also examined. Voltage gain was greatly dependent on the driving frequency and load resistance, and showed a maximum gain at resonance frequency of the step-down transformer. The frequency where the maximum cutout voltage appears increased about 0.2％ as the load resistance increased from 10 to 150 Ω. As the area of input electrode increased, the voltage gain and the efficiency of the transformer increased. Frequency dependence of efficiency of the step-down transformer revealed a similar tendency with the voltage gain curves. The maximum efficiency remarked 94% when the input voltage and the load resistance were 20 Vpp and 120 Ω, respectively.

• Journal of Hydrogen and New Energy
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• v.31 no.1
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• pp.8-22
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• 2020

In this study, we investigated the deactivation characteristics of Ni-Zn-Fe electrodes due to intermittent operation in alkaline water electrolysis. To find suitable method to accelerate deactivation of electrode, the accelerated stress-test (AST) which repeated on/off step was performed with constant current/voltage control. The AST under constant voltage control is suitable to deactivate electrode so it were selected to investigate deactivation of electrode. The AST which repeated on/off step in range of -1.3 V and 0 V was performed and the relationship between oxidation current and electrode deactivation in the off step was investigate. As results, it was confirmed that the nickel and zinc on electrode surface were oxidized due to anodic current which occurred at off step.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.722-725
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• 2004

Voltage step-down characteristics in Ring/Dot type piezoelectric transformer were examined as a function of the area of input electrode when the area of output electrode is fixed. The effects of driving frequency and load resistance on the voltage step-down characteristics were also examined. Voltage gain was greatly dependent on the driving frequency and load resistance, and showed a maximum gain at resonance frequency of the step-down transformer. The frequency where the maximum output voltage appears increased about 0.2% as the load resistance increased from 10 to $150\Omega$. As the area of input electrode increased, the voltage gain and the efficiency of the transformer increased. Frequency dependence of efficiency of the step-down transformer revealed a similar tendency with the voltage gain curves. The maximum efficiency remarked 94% when the input voltage and the load resistance were 20 $V_{PP}$ and $120\Omega$, respectively.

• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.73-78
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• 2017

A tetrode is one of the neural electrodes, and it is widely used to record neural signals in the brain of a freely moving animal. The impedance of a neural electrode is an important parameter because it determines the signal-to-noise ratio of the recorded neural signals. Here, we developed a modification technique using carbon nanotube-polypyrrole composite nanostructures to decrease the impedances of tetrodes. The synthesis of the carbon nanotube and polypyrrole nanostructures was performed in two steps. In the first step, randomly dispersed carbon nanotubes and pyrrole monomers were gathered and aligned on the tetrode electrode. Next, they were electro-polymerized on the electrode surface. As the applied time (step-1 and step-2) and the offset voltage increased, the impedances of the tetrodes decreased. The modification technique is, therefore, an important and useful of lowering the impedances of tetrodes.