• 전기화학회지
• /
• 제18권4호
• /
• pp.137-142
• /
• 2015

$Mn_{1+X}Co_{2-X}O_4$ solid solutions with various Mn/Co ratios were synthesized by a combustion method, and used as cathode catalysts for lithium/air secondary battery. Their electrochemical and physicochemical properties were investigated. The morphology was examined by transmission electron microscopy (TEM), and the crystallinity was confirmed by X-ray diffraction (XRD) analyses. For the measurement of electrochemical properties, charge and discharge measurements were carried out at a constant current density of $0.2mA/cm^2$, monitoring the voltage change. Electrochemical impedance spectroscopy (EIS) analyses were also employed to examine the change in charge transfer resistance during charge-discharge process. $Mn_{1+X}Co_{2-X}O_4$ solid solutions showed enhanced cycleability as a cathode of Li/air secondary battery, and the performance was found to be strongly dependent on Mn/Co ratio. Among synthesized catalysts, $Mn_{1.5}Co_{1.5}O_4$ exhibited the best performance and cycleability, due to high charge transfer rate.

• 전기화학회지
• /
• 제1권1호
• /
• pp.14-17
• /
• 1998

MPCF는 Li ion 2차전지용 부극 활물질로 연구되고 있다. 흑연화 MPCF는 높은 방전 용량과 우수한 충방전 효율을 가진다. $0\~1$ V전위영역에서 25 mA/g의 정전류로 충방전할 때의 MPCF/Li전지의 초기 방전 용량은 300 mAh/g이며, 충방전 효율은 $90\%$ 이상을 나타낸다. $LiCoO_2$을 정극 활물질로, 혼합 탄소재료를 부극 활물질로 사용하여 원통형 Li ion 2차전지를 제작하였다. Li ion 2차전지의 수명 특성을 향상하기 위하여, 흑연화 MPCF에 이종 탄소 재료를 $10 wt\%$ 혼합하였다. 혼합 탄소재료를 사용한 Li ion 2차전지의 수명 성능은 흑연화 MPCF만을 사용한 전지보다 우수하였다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2017년도 추계학술대회
• /
• pp.181-182
• /
• 2017

In the battery system, an isolated converter is used for the stability of the system when controlling the charge and discharge of the battery. A fixed frequency LLC converter which is a type of isolated converter, has the advantage of high efficiency and power density with zero voltage switching at high frequency. Therefore, in this paper, the operation analysis, design and experimental verification of the LLC resonant converter with high efficiency and high power density for the ESS system were conducted.

• 한국응용과학기술학회지
• /
• 제21권2호
• /
• pp.164-173
• /
• 2004

The capacity and long life of gel electrolyte batteries is connected with gas recombination producting $PbO_2$ and Pb electrode. We prepared with sulfuric acid gel electrolyte to know gel characteristics per density to assemble valve regulated lead-acid (VRLA) batteries. We studied on actions of sulphuric acid gel electrolyte by measuring electrolyte dispersion using Brewster-angle microscope (BAM), charge-discharge cycle, and electrode structure using scanning election microscope (SEM). Sulphuric acid density 1.210 showed excellent gel dispersion in sol condition, electrode condition after fifty cycles in this study.

• 한국응용과학기술학회지
• /
• 제20권4호
• /
• pp.296-308
• /
• 2003

The capacity and long life of gel electrolyte batteries is connected with gas recombination producting $PbO_2$ and Pb electrode. We were prepared with phosphoric acid gel electrolyte to know gel characteristics per density to assemble VRLA batteries. We studied by measuring electrolyte dispersion using Brewster-angle microscope(BAM), charge-discharge cycle and electrode structure using scanning election microscope(SEM) per electrolyte density. As a results, phosphoric acid density 1.210 was excellent gel dispersion in sol condition, electrode condition after fifty cycles in this study.

• 한국전기전자재료학회논문지
• /
• 제11권11호
• /
• pp.1049-1054
• /
• 1998

The LiCo$O_2$ powder was synthesized by a solution phase reaction. This shows a high (003) peak intensity and low (104) or (101) peak intensities in X-ray diffraction spectra. The LiCo$O_2$/Li cell shows an initial discharge capacity of 102.9mAh/g and an average discharge potential or 3.877V at a current density of 50mA/g between 3.0~4.2V. The peaks of dQ/dV plot are associated with Li ion intercalation/deintercalation reaction. To evaluate the cycleability of an actual battery system, cylindrical lithium ion cell was manufactured using graphitized MPCF anode and LiCoO$_2$ cathode. After 100th cycle, this cel maintains 80% capacity of 10th cycle value. The LiCoO$_2$/MPCF cell has a high discharge voltage of 3.6~3.7V and a good cycle life performance on cycling between 4.2~2.7V.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
• /
• pp.181.1-181.1
• /
• 2014

Supercapacitor is attracting growing attention for a promising energy conversion and storage device because of its desirable electrochemical properties such as rapid charge-discharge rate, high power density and long cycle life. Three-dimensional (3D) metal nanostructure has been widely studied since it can provide efficient charge transport along the 3D network in many device applications. In this work, we fabricated well-ordered 3D nickel (Ni) nanostructures using 3D-arrayed polystyrene nano-opal substrates. We also fabricated half-cell supercapacitors by electrodepositing $RuO_2$ onto these nanostructured Ni current collectors and investigated their morphological and electrochemical properties.

• 청정기술
• /
• 제20권4호
• /
• pp.433-438
• /
• 2014

전기자동차와 하이브리드 전기자동차에 요구되는 높은 충 방전 속도, 안전성, 대형화에 적합한 충 방전 전지의 개발은 많은 관심을 받고 있다. 스피넬 구조의 $Li_4Ti_5O_{12}$는 리튬이온이차전지의 음극활물질로 충 방전 시 부피변화가 거의 없기 때문에 수명특성이 뛰어나고, 전해액이 분해되는 전위보다 높은 작동 전압을 갖기 때문에 안정한 장점이 있다. 본 실험에서는 $Li_4Ti_5O_{12}$의 단점인 전기전도성을 향상시키고자 소량의 Ru를 첨가하여 $Li_4Ti_5O_{12}$를 고상법으로 제조하여 테스트하였다. TGA-DTA, XRD, SEM, 충 방전 테스트를 통해 분석을 실시하였다. Ru를 첨가하였을 때 용량은 약간 감소하였지만, 분극현상이 감소하는 것을 확인하였다. 그리고 Ru를 3%와 4% 첨가하였을 때 높은 전류밀도인 10 C-rate 충 방전에서 용량감소율이 줄었다.

• 한국재료학회지
• /
• 제32권12호
• /
• pp.545-552
• /
• 2022

Tin-antimony sulfide nanocomposites were prepared via hydrothermal synthesis and a N₂ reduction process for use as a negative electrode in a sodium ion battery. The electrochemical energy storage performance of the battery was analyzed according to the tin-antimony composition. The optimized sulfides exhibited superior charge/discharge capacity (770 mAh g^-1 at a current density of 100 mA g^-1) and stable lifespan characteristics (71.2 % after 200 cycles at a current density of 500 mA g^-1). It exhibited a reversible characteristic, continuously participating in the charge-discharge process. The improved electrochemical energy storage performance and cycle stability was attributed to the small particle size, by controlling the composition of the tin-antimony sulfide. By optimizing the tin-antimony ratio during the synthesis process, it did not deviate from the solubility limit. Graphene oxide also acts to suppress volume expansion during reversible electrochemical reaction. Based on these results, tin-antimony sulfide is considered a promising anode material for a sodium ion battery used as a medium-to-large energy storage source.

• 한국재료학회지
• /
• 제31권2호
• /
• pp.84-91
• /
• 2021

To cope with automobile exhaust gas regulations, ISG and charging control systems are applied to HEV vehicles for the purpose of improving fuel economy. These systems require quick charge-discharge performance of high current. Therefore, a Module of the AGM battery with high energy density and EDLC(Electric Double Layer Capacitor) with high power density are constructed to study the charging and discharging behavior. In CCA, which evaluates the starting performance at -18 ℃ & 30 ℃ with high current, EDLC contributed for about 8 sec at the beginning. At 0 ℃ CA (Charge Acceptance), the initial Charging current of the AGM/EDLC Module, is twice that of the AGM lead acid battery. To play the role of EDLC during high-current rapid charging and discharging, the condition of the AGM lead-acid battery is optimally maintained. As a result of a Standard of Battery Association of Japan (SBA) S0101 test, the service life of the Module of the AGM Lead Acid Battery/EDLC is found to improve by 2 times compared to that of the AGM Lead Acid Battery.