• 전기학회논문지
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• 제66권2호
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• pp.357-362
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• 2017

Among the lithium metal oxides for asymmetric hybrid supercapacitor, $Li_4Ti_5O_{12}(LTO)$ is an emerging electrode material as zero-stain material in volume change during the with the charging and discharging processes. The pulverized LTO powder was observed to show the enhanced capacity from 120 mAh/g to 156 mAh/g at C-rate (10, 100 C). Hybrid supercapacitor module(48V, 416F) was fabricated using an asymmetric hybrid capacitor with a capacitance of 7500F. As a result of the measurement of C-rate characteristics, the module shows that the discharge time is drastically reduced at more than 50C, and the ESR and voltage drop characteristics are increased. The energy density and power density were reduced under high C-rate conditions. When designing asymmetric hybrid supercapacitor module, the C-rate and ESR should be considered As a result of measuring the 5 kw UPS, it was discharged at the current of 116A~170A during the discharge in the voltage range of 48V~30V, and the compensation time at discharge was measured to be about 33.2s. Experimental results show that it can be applied to applications related to stabilization of power quality by applying hybrid supercapacitor module.

• 전기학회논문지
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• 제65권4호
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• pp.617-621
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• 2016

In addition to the energy storage facilities based on high power technologies, Electric double layer capacitors(EDLC) are today's candidate for power quality stabilization. However, its low energy density is often inhibiting factor for application of electric power industry. Hybrid supercapacitor is an promising energy storage device that positioned between conventional EDLC and Li-ion battery. This paper describes the preparation and characteristics of a hybrid supercapacitor and module for power quality stabilization. A cylindrical 3200F hybrid supercapacitor ($60{\times}74.5mm$) was assembled by using the $Li_4Ti_5O_{12}$ electrode as an anode and activated carbon as a cathode. It shows 2.5 times higher energy density than conventional EDLC with the same volume. In order to determine the characteristics of the hybrid supercapacitor Module for uninterruptible power supply (UPS), hybrid supercapacitor cells were connected in series with active balancing circuit. At even the high current density of 14A(10C), Module prepared by 18 cells showed the capacitance of 170F at 30~50V, suggesting the applicability for UPS.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.597-598
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• 2005

Recently, the performance of portable electric equipment can often improved by a Li-ion battery assisted by a supercapacitor. A supercapacitor can provide high power density as well as a low resistance in the hybrid system. In this study, we have prepared, as the pluse power souce, a commercially supplied Li-ion battery with a capacity of 700mAh and AC resistivity of $60m\Omega$ at 1kHz and nonaqeous asymmetric hybrid capacitor composed of an activated carbon cathode and MCMB anode, and have examined the electrochemical characteristics of hybrid capacitor and the pulse performances of parallel connected battery/hybrid capacitor source. The nonaqueous asymmetric hybrid capacitor, the stacks of 10 pairs of the cathode, the porous separator and the anode electrode were housed in Al-laminated film cell. The hybrid capacitor, which was charged and discharged at a constant current at $0.25mA/cm^2$ between 3 and 4.3V, has exhibited the capacitance of 100F. And the equivalent series resistance was $32m\Omega$ at 1kHz. By combining a Li-ion battery and a hybrid capacitor, the pulse performance of battery can be improved 23% in run time under a pulse discharge of 7C-rate.

• Journal of Electrochemical Science and Technology
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• 제2권3호
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• pp.152-156
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• 2011

A hybrid supercapacitor is fabricated using a composite material from $LiMn_2O_4$ (LMO) and activated carbon (AC) as the positive electrode and AC as the negative electrode to form the (LMO + AC)/AC system. Volume ratio (positive : negative) of electrodes is controlled to investigate of the power and energy balance. The (LMO + AC)/AC system shows better performances than the LMO/AC system. Especially, electrochemical impedance spectra, rate charge.discharge and cycle performance testing show that the (LMO + AC)/AC system have an outstanding electrochemical performance at volume ratios of (LMO + AC)/AC = 1 : 1.7 and 1 : 2. Electric double layer capacitor (EDLC) capacitance between AC of the positive electrode and AC of the negative electrode improves power density without loss of capacitance. Stable capacitance is achieved by lowering the positive electrode resistance and balancing the energy and power densities between the positive and negative electrodes by the addition of AC to the positive electrode at high current density.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2005년도 춘계총회 및 학술발표회
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• pp.16-16
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• 2005

• 한국재료학회지
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• 제29권12호
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• pp.774-780
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• 2019

The performance of Li-ion hybrid supercapacitors (asymmetric-type) depends on many factors such as the capacity ratio, material properties, cell designs and operating conditions. Among these, in consideration of balanced electrochemical reactions, the capacity ratio of the negative (anode) to positive (cathode) electrode is one of the most important factors to design the Li-ion hybrid supercapacitors for high energy storing performance. We assemble Li-ion hybrid supercapacitors using activated carbon (AC) as anode material, lithium manganese oxide as cathode material, and organic electrolyte (1 mol L^-1 LiPF₆ in acetonitrile). At this point, the thickness of the anode electrode is controlled at 160, 200, and 240 ㎛. Also, thickness of cathode electrode is fixed at 60 ㎛. Then, the effect of negative and positive electrode ratio on the electrochemical performance of AC/LiMn₂O₄ Li-ion hybrid supercapacitors is investigated, especially in the terms of capacity and cyclability at high current density. In this study, we demonstrate the relationship of capacity ratio between anode and cathode electrode, and the excellent electrochemical performance of AC/LiMn₂O₄ Li-ion hybrid supercapacitors. The remarkable capability of these materials proves that manipulation of the capacity ratio is a promising technology for high-performance Li-ion hybrid supercapacitors.