• 한국전기화학회:학술대회논문집
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• 한국전기화학회 1999년도 전지기술심포지움
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• pp.83-91
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• 1999

Technical advances in manufacturing techniques and applied technologies have been made for bi cell manufacture, and are currently being implemented in the areas of discrete electrode / bi cell assembly, and electrode / separator lamination. Not only have improvements been noted in the reliability of the mechanical assembly and the increase in yields and decrease in costs, battery electrical performance has also been enhanced thru these assembly techniques. Evidence has been shown that the lamination techniques can influence porosity and electrolyte dispersion, and therefore electrical performance and long term reliability of the cells.

• 한국환경과학회지
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• 제6권1호
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• pp.1-8
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• 1997

Varing the flow velocity of solution and particle diameter, the mass transfer coefficient of the local electrode on current feeder has been measured in an empty flow reactor, an inert fluidized bed electrode reactor, and an active fluidized bed electrode reactor. It had its maximium value when the bed porosity was 0.6 to 0.65 and decreased with in- creasing the height of local electrode. The mass transfer coefficient was found to be high especially when higher particle was fluidized. Electrochemical deposition of copper dissolved in the synthesized wastewater has been performed in the active fluidized bed electrode reactor. The deduction rate was higher than 90% and the residual concentration of copper decreased to less than 5ppm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.307-310
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• 1991

• 한국진공학회지
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• 제15권3호
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• pp.273-279
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• 2006

Si기반 고주파집적회로의 차단재로서 간접전극 양극산화법으로 형성된 다공성 Si을 활용하기 위한 기초 연구로서 전류밀도, 시간에 따른 기공의 크기와 깊이등을 조사하였고 기공 도입 전,후 Si의 격자상수 변화를 측정하여 유발되는 내부응력의 크기를 평가하였다. 기공의 크기와 깊이는 대개 전류밀도와 시간에 따라 증가하였다. 기공이 형성됨에 따라 Si의 격자상수가 증가하여 약 8MPa의 압축응력이 유발되었다. 간접전극 양극산화법으로 형성된 다공성 Si은 공정이간단하고 기공으로 유발되는 내부응력의 크기가 작아 Si YLSI공정 적합성이 우수하므로 고주파 직접회로의 효과적인 차단재로서 적합한 재료로 판단된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1291-1292
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• 2007

Recently, there were many researches for efficiency improvement of DSC. Among of these works, research of surface treatment is still a prerequisite for electron diffusion, light-harvesting and surface state of DSC.[1] Using of the surface treatment, it can be raise up porosity of $TiO_2$ nano-crystalline structure on photo-electrode. There are chemical, physical, electrical and optical methods which raise up its porosity. In this paper, we have designed and manufactured MOPA-type ultrasonic circuit (100W, frequency and duty variable). Manufactured ultrasonic circuit to use to force cavity density and power into $TiO_2$ paste. Then, we have optimized forcing time, frequency and duty of ultrasonic irradiation for surface treatment of photo-electrode of DSC. In I-V characteristic test of DSC, ultrasonic and thermal treated DSC shows 19% improved its efficiency against monolithic DSC. And it shows stability of light-harvesting from drastically change of light irradiation test.

• Journal of Electrochemical Science and Technology
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• 제15권1호
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• pp.111-131
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• 2024

Lignin-derived porous carbon has been identified as a versatile electrode material for supercapacitors (SCs) in energy storage systems (ESSs) owing to their intrinsic advantages including good electrical conductivity, low cost, high thermal and chemical stability, and high porosity, which stem from high surface, appropriate pore distribution, tailored morphologies, heterostructures, and diverse derivates. In this review, to provide a fundamental understanding of the properties of lignin, we first summarize the origin, historical development, and basic physicochemical properties. Next, we describe essential strategies for the preparation of lignin-derived porous carbon electrode materials and then highlight the latest advances in the utilization of lignin-derived porous carbon materials as advanced electrode materials. Finally, we provide some of our own insights into the major challenges and prospective research directions of lignin-derived porous carbon materials for supercapacitors. We believe that this review will provide general guidance for the design of next-generation electrode materials for supercapacitors.

• 한국표면공학회지
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• 제28권2호
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• pp.83-91
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• 1995

A new method for preparation of thin nickel foam for Ni-MH battery was investigated. In this method, fine graphite powders of $1\mu\textrm{m}$～$2\mu\textrm{m}$ diameter were pasted into pores of thin polyurethane foam film in order to supply electric conducting seeds for nickel deposition by electroless plating reaction. After electroless plating, remaining polyurethane foam was removed chemically by organic solvent treatment and graphite particles also removed by ultrasonic cleaning. Porosity of formed nickel foam was about 85% During electroplating, porosity of the nickel foam decreased less than 5% up to $30\mu\textrm{m}$ coating thickness. And then it was electroplated and heat-treated to improve mechanical strength and ductility. Finally, thin nickel foam for Ni electrode of Ni-MH battery with 80% porosity and $350\mu\textrm{m}$～X$400\mu\textrm{m}$ thickness was obtained.

• 대한기계학회논문집B
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• 제38권4호
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• pp.357-363
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• 2014

리튬이온전지의 다공성 전극내에서 전해액 주입 후 발생하는 함침현상에 관하여 격자 볼츠만법을 이용하여 수치해석적으로 연구하였다. 다공성 전극은 전극 제조 중 압연공정을 거치므로 압축된 전극의 공극률과 두께변화가 발생하여 전해액 함침성에 영향을 미치게 된다. 본 연구에서는 2 차원 격자 볼츠만법을 통하여 압축률에 따른 전해액 분포와 포화도 변화를 제시하였다. 압축된 전극에서의 전해액 침투경로의 변화는 기공의 두께방향 크기 감소에 기인하며, 따라서 전극의 함침성이 크게 감소하였음을 확인하였다.

• 한국기계가공학회지
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• 제21권9호
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• pp.85-91
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• 2022

The demand for electric vehicles has increased because of environmental regulations. The lithium-ion battery, the most widely used type of battery in electric vehicles, is composed of a cathode, an anode, and an electrolyte. It is manufactured according to the pole plate, assembly, and formation processes. To improve battery performance and increase manufacturing efficiency, the manufacturing process must be optimized. To do so, simulation can be used to reduce wasted resources and time, and a finite-element method can be utilized. For high simulation quality, it is essential to reflect the material properties of the electrode by considering the pores. However, the material properties of electrodes are difficult to derive through measurement. In this study, the representative volume element method, which is a homogenization method, was applied to estimate the representative material properties of the electrode considering the pores. The representative volume element method assumes that the strain energy before and after the conversion into a representative volume is conserved. The method can be converted into one representative property, even when nonhomogeneous materials are mixed in a unit volume. In this study, the material properties of the electrode considering the pores were derived. The results should be helpful in optimizing the electrode manufacturing process and related element technologies.

• 전기화학회지
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• 제24권2호
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• pp.28-33
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• 2021

이차전지의 에너지 밀도를 높이기 위한 방법으로 전극의 로딩을 높이는 방법에 대하여 많은 시도가 이루어지고 있다. 본 연구에서는 리튬이온 이차전지용 양극에서 보편적으로 사용되어 온 기존의 polyvinylidene fluoride (PVdF) 바인더가 아닌 polytetrafluoroethylene (PTFE) 바인더를 적용하여 고로딩의 LiNi_0.5Co_0.2Mn_0.3O₂ (NCM523) 양극을 제조하였다. 기존의 슬러리 공정이 아닌 PTFE 현탁액을 이용한 반죽공정을 통하여 로딩을 높인 두꺼운 전극이 용이하게 제조되었다. PTFE 및 PVdF 기반의 전극을 5.0 mAh/cm²의 로딩레벨로 각각 제조한 결과로 PTFE를 적용한 전극이 좀 더 우수한 사이클 수명과 속도특성을 지니고 있음을 확인하였다. PTFE 바인더를 사용한 반죽공정으로 제조된 전극은 기공도가 커서 전극밀도가 높지 않기 때문에 압연을 상온이 아닌 120℃ 이상의 고온에서 진행함으로써 기공도를 낮출 수 있었으나, 이에 따른 사이클 성능의 차이는 크지 않았다. 또한, 전극조성에서 도전재의 함량을 높임으로써 고로딩 전극의 사이클 수명을 소폭 향상시킬 수 있었다. PTFE 바인더 적용으로 고로딩 전극의 성능을 향상시킬 수 있었으나, 추가적인 개선이 필요할 것이다.