• 청정기술
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• 제22권4호
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• pp.308-315
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• 2016

수명특성이 우수한 실리콘 음극재를 제조하기 위해 졸겔법을 통해 $SiO_x/ZnO$ 복합체를 제조하였고, 제조된 복합체는 PVC를 탄소 전구체로 하여 탄소를 피복하였다. 복합체에 포함된 ZnO를 HCl로 제거하여 내부에 빈 공간을 만들어 충 방전에 따른 실리콘의 부피변화를 완화할 수 있게 하였다. 합성된 복합체의 결정구조와 형상을 파악하기 위해 XRD, SEM, TEM 분석을 실시하였다. 탄소 피복된 복합체에 포함된 탄소함량을 TGA를 통해 알아보았으며, 복합체의 기공구조를 확인하기 위해 BET 비표면적 분석과 BJH 기공분포를 확인하였다. 탄소의 추가로 향상된 전기전도성을 측정하였으며, 전기화학적 특성은 AC 임피던스 측정과 충 방전 및 수명특성을 확인하였다. $SiO_x/ZnO$시료에 탄소를 피복할 경우에 전기전도도가 증가하였으며, 방전용량도 증가하였다. 염산으로 ZnO를 제거한 시료의 경우에 표면적은 증가하였으나, 전지의 방전용량은 오히려 감소하였다. 탄소를 피복하지 않은 $SiO_x/ZnO$ 시료의 경우에 방전용량이 매우 낮았으며, 탄소를 피복한 후의 시료는 높은 충방전용량을 나타내었다. 수명특성의 경우, $C-SiO_x/ZnO$ 복합체(Zn : Si : C = 1 : 1 : 8)가 0.2 C의 전류량에서 50 사이클에서 $815mAh\;g^{-1}$의 용량으로 기존 흑연계 음극재보다 높은 용량을 나타내었다.

• 공업화학
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• 제30권1호
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• pp.11-16
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• 2019

Ni-benzene-1,3,5-tricarboxylic acid based metal organic frameworks were successfully synthesized by hydrothermal method and thermally treated at various temperature. The electrochemical performance of composites was investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. Among all prepared composites, the samples annealed at $250^{\circ}C$ showed the highest capacitance with a low resistance, and high cycle stability. It was possible to obtain the low electrical resistance and high electric conductivity of the electrode by improved microstructure and morphology after the thermal annealing at $250^{\circ}C$. The samples annealed at $250^{\circ}C$ also displayed the maximum specific capacitance with a value of $953Fg^{-1}$ at a current density of $0.66A/g^{-1}$ in 6 M KOH electrolyte. Moreover, a 86.4% of the initial specific capacitance of the composite was maintained after 3,000 times charge-discharge cycle tests. Based on these properties, it can be concluded that the composite could be applied as potential supercapacitor electrode materials.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.368-369
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• 2006

The pure $LiFePO_4$, carbon added $LiFePO_4(LiFePO_4/C$) and pyrene added $LiFePO_4(LiFePO_4/P$) are synthesized by using solid-state reaction. XRD patterns show no impurity phase in the three kinds of the cathode materials. The 10wt% pyrene added $LiFePO_4$ shows around 140mAh/g of discharge capacity at 3rd cycle compared to the pure $LiFePO_4$. The carbon added $LiFePO_4$ shows 145mAh/g of discharge capacity at 3rd cycle and stable cycle-life compared to the others.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1703-1706
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• 1996

The purpose of this study is to research and develop polypyrrole(PPy) positive for thin film rechargeable lithium battery. We investigated cyclic voltammetry, AC impedance response and charge/discharge cycling of PPy/SPE/Li cells as a function of temperature. The redox capacity of $PPy/CF_{3}SO_{3}$ film was the most large. The discharge capacity of PPy/SPE/Li cell with $PPy/CF_{3}SO_{3}$ film was higher than those of $PPy/ClO_{4}$ and $PPy/AsF_6$ films at all cycles. The energy density of PPy/SPE/Li cells during 1st cycle was 73, 90 and 101Wh/kg at $25^{\circ}C$, $45^{\circ}C$ and $60^{\circ}C$, respectively. The improvement of energy density is due to reduction of charge-transfer resistance associated doping-undoping process in PPy film with Increasing temperature. $PPy/CF_{3}SO_{3}$ film shows a good property on charge/discharge cycling in PEO-$LiClO_4$-PC-EC electrolyte.

• 한국재료학회지
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• 제31권2호
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• pp.75-83
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• 2021

To cope with automobile exhaust gas regulations, ISG (Idling Stop & Go) and charging control systems are applied to HEVs (Hybrid Electric Vehicle) for the purpose of improving fuel economy. These systems require quick charge/discharge performance at high current. To satisfy this characteristic, improvement of the positive electrode plate is studied to improve the charge/discharge process and performance of AGM(Absorbent Glass Mat) lead-acid batteries applied to ISG automotive systems. The bonding between grid and A.M (Active Material) can be improved by applying the Sand-Blasting method to provide roughness to the surface of the positive grid. When the Sand-Blasting method is applied with conditions of ball speed 1,000 rpm and conveyor speed 5 M/min, ideal bonding is achieved between grid and A.M. The positive plate of each condition is applied to the AGM LAB (Absorbent Glass Mat Lead Acid Battery); then, the performance and ISG life characteristics are tested by the vehicle battery test method. In CCA, which evaluates the starting performance at -18 ℃ and 30 ℃ with high current, the advanced AGM LAB improves about 25 %. At 0 ℃ CA (Charge Acceptance), the initial charging current of the advanced AGM LAB increases about 25 %. Improving the bonding between the grid and A.M. by roughening the grid surface improves the flow of current and lowers the resistance, which is considered to have a significant effect on the high current charging/discharging area. In a Standard of Battery Association of Japan (SBA) S0101 test, after 300 A discharge, the voltage of the advanced AGM LAB with the Sand-Blasting method grid was 0.059 V higher than that of untreated grid. As the cycle progresses, the gap widens to 0.13 V at the point of 10,800 cycles. As the bonding between grid and A.M. increases through the Sand Blasting method, the slope of the discharge voltage declines gradually as the cycle progresses, showing excellent battery life characteristics. It is believed that system will exhibit excellent characteristics in the vehicle environment of the ISG system, in which charge/discharge occurs over a short time.

• 전기화학회지
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• 제3권2호
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• pp.121-126
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• 2000

[ $AB_5$ ] 수소저장합금인 $LaNi_5$, 합금분말에 Ni 및 Cu 무전해 도금의 영향을 전기 화학적 실험을 통하여 고찰하였다. 전기 화학적 실험은 정전류 충$\cdot$방전 실험, 순환전류전위 실험, 교류 임피던스 실험 등을 실시하여 도금하지 않은 $LaNi_5$ 전극과 Ni 및 Cu 무전해 도금한 전극간의 특성을 비교 연구하였다. 현상학적인 분석으로는 SEM을 이용하여 분말상의 미세조직을 관찰하였으며 X-선 회절시험을 실시하였다 무전해 도금을 실시하여 Ni 및 Cu박막이 피복된 수소저장 합금은 활성화 특성파 싸이클 수명 등의 특성이 개선되었으며 도금하지 않은 전극에 비하여 반응속도가 증가하였다. 또한 충$\cdot$방전이 반복됨에 따라 전극과 전해질 계면에서의 전하이동저항이 현저하게 감소하였다. 따라서 본 연구에서 실시한 $LaNi_5$, 활물질에 Ni및 Cu 무전해 도금을 실시하면 초기 활성화반응을 촉진시키며 $LaNi_5$활물질이 전해질과의 직접 접촉을 피하게 되어 전극의 수명을 증가시키는 것을 알 수 있었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.934-937
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• 1998

Charge/discharge property of LiMn2O4 was investigated with LiMn2O4/Li cell for use of lithium ion battery in electric vehicle. LiMn2O4 calcined at $800^{\circ}C$ for 36hr show high charge/discharge capacity and excellent cycle stability than that of others. This is found to be in agreement with expectation in the X-ray diffraction analysis. In addition, the kind and volume of conductive agent involved in LiMn2O4 cathode is excellent at super-s-black and 20wt%, respectively.

• 전기학회논문지P
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• 제59권3호
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• pp.288-292
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• 2010

Recently, in energy storage system, the EDLC is paid attention as a new environmentally friendly energy storage element. This capacitor has higher energy density than the electrolytic capacitor. Also, this capacitor has a lot of advantage such as no maintenance, longer life cycle and faster charge-discharge time than the battery system. But the EDLC must have a each charge-discharge controller to effectively control, an energy design method circuit to use effectively energy, and several compensation techniques to control a optimal operating. In this respect, this study suggests major parameters to effectively represent the characteristics of EDLC, the measurement methods of those parameters have been investigated with experiments, and the interpretation about the buck/boost DC/DC converter for the operation of EDLC.

• 한국수소및신에너지학회논문집
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• 제5권1호
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• pp.1-8
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• 1994

Lattice structure, hydrogen absorption characteristics, discharge capacity and cycle life of $V_{22}Ti_{16}Zr_{16}Ni_{39}X_7$(X= Cr, Co, Fe, Mn, Al) alloys were investigated. The matrix phases of these alloys were the C14 Laves phase. Chromium-containing alloy had a vanadium-rich phase in addition to the Laves phase. The chromium, maganese, or aluminum-containing alloys had lower hydrogen equilibrium pressure and larger hydrogen absorption content than the cobalt or iron-containing alloys. The discharge capacities of these alloys were 270~330mAh/g. The discharge capacity according to the alloying element X decreased in the order of Mn>Cr>Co, Al)Fe. The charge/discharge cycle lives of the chromium, cobalt or iron-containing alloys were longer than those of maganese or aluminum-containing alloys due to the lower vanadium dissolution rate.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.350-351
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• 2007

The $LiFePO_4$ as cathode materials for lithium ion batteries was synthesized by the solid-state reaction using ballmiller and employed one step heat treatment at $650^{\circ}C$. The influence of the heating time on the structure, particle size and cycle performance was investigated. $LiFePO_4$ heated at $650^{\circ}C$ for 3 h exhibited higher discharge capacity of 140 mAh/g and excellent cycle performance.