• 한국전기화학회:학술대회논문집
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• 한국전기화학회 1999년도 제2회 총회 및 춘계학술발표회
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• pp.73-73
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• 1999

• 한국수소및신에너지학회논문집
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• 제22권1호
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• pp.83-91
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• 2011

We investigated the effect of composition of a sulfur electrode with MWNT on the discharge behavior and cycling property of a Li/S cell. The MWNT content of a 60wt.% sulfur electrode varied from 10 wt.% to 30 wt.%. The optimum content of MWNT is 20wt.%, which shows the best cycling property. The first discharge capacity is 1166 mAh/g and decrease to the 542 mAh/g after 30th cycle. The homogeneous distribution of MWNT is an important factor for cycling properties.

• 공업화학
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• 제9권4호
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• pp.486-490
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• 1998

콜로이드법을 이용하여 인산형 연료전지에서 전극촉매로 사용되는 Pt/C 분말을 제조하였다. 이 때 환원제로 사용되는 $Na_2S_2O_4$ (sodium hydrosulfite)로부터 유입되는 황성분이 연료전지의 장기운전시 촉매독으로 작용하는 것으로 알려져 었다. 따라서 다음의 3가지 방법을 이용하여 황을 제거하였다. 첫 번째, 열처리에 의한 황의 제거시 온도가 올라갈수록 황의 제거 효과가 좋지만 너무 높은 온도에서는 백금입자의 크기가 성장하여 입자의 크기가 $50{\AA}$ 이상이 되면 전극성능이 감소하였다. 최적의 열처리 온도는 $400^{\circ}C$ 이었으며, 이 때의 백금입자의 크기는 $35{\sim}40{\AA}$였으며, 반전지 측정시 0.7V의 전압에서 $360mA/cm^2$의 전류밀도를 나타내었다. $400^{\circ}C$에서 1시간, 3시간, 5시간 동안 처리하였을 경우 백금입자의 크기는 변함이 없었고 황제거율은 각각 비슷하였다. 두 번째, 환원성 분위기의 도가니 속에서 열처리를 했을 경우 $900^{\circ}C$의 같은 온도에서 수소분위기에서의 열처리보다는 황의 제거율은 떨어지나 같은 온도에서 백금입자의 성장이 작아 상대적으로 좋은 전극성능을 보여 주었다. 세 번째, 용매추출의 경우에는 초기에 일부의 황을 제거할 수 있음을 확인하였고 이 때의 전극성능은 서로 비슷하였다.

• Korean Chemical Engineering Research
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• 제61권3호
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• pp.426-438
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• 2023

차세대 전지로 주목받는 리튬-황 전지는 높은 에너지 밀도를 갖는 반면, 황의 절연 특성, 셔틀 현상 그리고 부피팽창으로 인하여 상용화에 어려움이 있다. 본 연구에서는 경제적이고 간단한 진공여과 방법으로 바인더와 집전체가 없는 프리스탠딩 전극을 제조하였고 탄소나노튜브(CNT)를 황의 전기전도도 향상을 위하여 사용하였다. 여기서 CNT는 집전체와 도전재 역할을 동시에 수행하였다. 추가로 리튬폴리설파이드의 흡착에 용이한 금속산화물(MO_x, M=Ni, Mg)을 CNT/S 전극에 첨가함으로써 리튬-황 전지의 셔틀반응을 억제하였다. MO_x@CNT/S 전극은 금속산화물을 도입하지 않은 CNT/S 전극에 비해 높은 용량 특성과 사이클 안정성을 나타내었으며, 이는 금속산화물의 우수한 리튬폴리설파이드 흡착 특성으로 인하여 황 활물질의 손실을 억제한 결과이다. MO_x@CNT/S 전극 중에서 NiO를 도입한 NiO@CNT/S 전극은 1 C에서 780 mAh g^-1의 높은 방전용량을 나타내었고 200 사이클 후 134 mAh g^-1으로 극심한 용량 감소가 나타났다. MgO@CNT/S 전극은 비록 초기 사이클에 544 mAh g^-1의 낮은 방전용량을 나타냈지만, 200 사이클까지 용량을 90% 유지하는 우수한 사이클 안정성을 나타내었다. 고용량과 사이클 안정성 확보를 위하여 Ni:Mg를 0.7:0.3의 비율로 혼합한 Ni_0.7Mg_0.3O@CNT/S 전극은 755 mAh g^-1 (1 C)의 초기 방전용량과 200 사이클 후에도 90% 이상의 용량 유지율을 나타내었다. 따라서 이원 금속산화물의 CNT/S 프리스탠딩으로의 적용은 고용량 특성뿐만 아니라 가장 큰 문제인 리튬폴리설파이드의 용출을 효과적으로 개선하여 경제적이고 고성능 리튬-황 전지의 개발이 가능함을 시사한다.

• 한국재료학회지
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• 제16권3호
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• pp.193-197
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• 2006

The sodium/sulfur(Na/S) battery has many advantages such as high theoretical specific energy(760Wh/kg), and low material cost based on the abundance of electrode material in the earth. It has been reported that the electrochemical properties of sodium/sulfur cell above $300^{\circ}C$, utilized a solid ceramic electrolyte and liquid sodium and sulfur electrodes. A lot of researches have been performed in this field. Recently, Na/S battery system was applied for electricity storage system for load-leveling. One of severe problems of sodium/sulfur battery was high operating temperature above $300^{\circ}C$, which could induce the explosion and corrosion by molten sodium, sulfur and polysulfides. In order to develop sodium battery operated at low temperature, sodium ion battery has been studied using carbon anode, and sodium oxides cathodes. However, the energy densities of the sodium ion batteries were much lower than high temperature sodium/sulfur cell. In this study, the sodium/sulfur battery with 1M $NaCF_3SO_3$ is tested at room temperature. The charge-discharge mechanism was discussed based on XRD, DSC, SEM and EDS results.

• 대한안전경영과학회지
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• 제16권2호
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• pp.237-246
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• 2014

Researches on the elimination of sulfur and nitrogen oxides with catalysts and absorbents reported many problems related with elimination efficiency and complex devices. In this study, decomposition efficiency of harmful gases was investigated. It was found that the efficiency rate can be increased by moving the harmful gases together with SPCP reactor and the catalysis reactor. Calcium hydroxide($Ca(OH)_2$), CaO, and $TiO_2$ were used as catalysts. Harmful air polluting gases such as $SO_2$ were measured for the analysis of decomposition efficiency, power consumption, and voltage according to changes to the process variables including frequency, concentration, electrode material, thickness of electrode, number of electrode winding, and additives to obtain optimal process conditions and the highest decomposition efficiency. The standard sample was sulfur oxide($SO_2$). Harmful gases were eliminated by moving them through the plasma generated in the SPCP reactor and the $Ca(OH)_2$ catalysis reactor. The elimination rate and products were analyzed with the gas analyzer (Ecom-AC,Germany), FT-IR(Nicolet, Magna-IR560), and GC-(Shimazu). The results of the experiment conducted to decompose and eliminate the harmful gas $SO_2$ with the $Ca(OH)_2$ catalysis reactor and SPCP reactor show 96% decomposition efficiency at the frequency of 10 kHz. The conductivity of the standard gas increased at the frequencies higher than 20 kHz. There was a partial flow of current along the surface. As a result, the decomposition efficiency decreased. The decomposition efficiency of harmful gas $SO_2$ by the $Ca(OH)_2$ catalysis reactor and SPCP reactor was 96.0% under 300 ppm concentration, 10 kHz frequency, and decomposition power of 20 W. It was 4% higher than the application of the SPCP reactor alone. The highest decomposition efficiency, 98.0% was achieved at the concentration of 100 ppm.

• 신재생에너지
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• 제16권4호
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• pp.1-8
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• 2020

The possibility of conversion to the RC-MAT propulsion system (gasoline engine → electric motor) was studied. However, as commercial battery capacities are low. it is not possible to change the propulsion system. Nevertheless, development of nex-generation batteries is necessary for high capacity and high energy density. Although Li/S batteries are theoretically suitable as new generation batteries, these batteries are not composed of only Li and S. Hence, ensuring high energy density can be difficult. Moreover, electrolytes are important components in the study of energy density; hence, the battery by Li2S8 Molarity was sorted. There are no studied on its various electrode components. In this study, a Li/S battery was fabricated using an assorted 3D sulfur electrode of high energy density and its electrochemical properties were studied. The Li/S battery has a high energy density of 468 Wh/kg at 1.28 M Li2S8 (A805-1.28). Its capacity rapidly decreased after 1 cycle with more than 1 M Li2S8.

• Journal of Electrochemical Science and Technology
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• 제7권2호
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• pp.97-114
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• 2016

Lithium batteries based on elemental sulfur as the cathode-active material capture great attraction due to the high theoretical capacity, easy availability, low cost and non-toxicity of sulfur. Although lithium/sulfur (Li/S) primary cells were known much earlier, the interest in developing Li/S secondary batteries that can deliver high energy and high power was actively pursued since early 1990’s. A lot of technical challenges including the low conductivity of sulfur, dissolution of sulfur-reduction products in the electrolyte leading to their migration away from the cathode, and deposition of solid reaction products on cathode matrix had to be tackled to realize a high and stable performance from rechargeable Li/S cells. This article presents briefly an overview of the studies pertaining to the different aspects of Li/S batteries including those that deal with the sulfur electrode, electrolytes, lithium anode and configuration of the batteries.

• 전기화학회지
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• 제21권1호
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• pp.6-11
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• 2018

다양한 전자제품에서 높은 성능의 이차 전지가 요구됨에 따라 안전하고 친환경적이며 경제적인 이차 전지 전극 재료의 개발을 필요로 하고 있다. 리튬-황 배터리는 높은 이론용량과 에너지밀도, 그리고 친환경적인 물질이라는 점에서 차세대 이차전지로써 주목받고 있지만, 폴리설파이드의 용출로 인한 전지 용량감소현상이 일어나고, 황의 부도체 특성으로 인해 아직 상용화 단계에 미치지 못하고 있다. 본 연구에서는 보다 향상된 이차 전지 전극 재료로서 다른 양극 물질들에 비해 에너지 밀도가 높은 황을 양극재로 사용하여 전지를 만들고 이 때 양극 활물질의 구성요소인 황, 도전재, 바인더의 비율을 다양하게 변화하면서 양극을 제조하고 여러 전기화학적 평가를 거쳐 가장 좋은 전지 성능을 낼 수 있는 구성성분 비율을 모색하고자 하였다.

• Journal of Electrochemical Science and Technology
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• 제12권2호
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• pp.279-284
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• 2021

The high theoretical specific capacity of lithium-sulfur (Li-S) batteries makes them a more promising energy storage system than conventional lithium-ion batteries (LIBs). However, the slow kinetics of the electrochemical conversion reaction seriously hinders the utilization of Li-S as an active battery material and has prevented the successful application of Li-S cells. Therefore, exploration of alternatives that can overcome the sluggish electrochemical reaction is necessary to increase the performance of Li-S batteries. In this work, an ionic liquid (IL) is proposed as a functional additive to promote the electrochemical reactivity of the Li-S cell. The sluggish electrochemical reaction is mainly caused by precipitation of low-order polysulfide (l-PS) onto the positive electrode, so the IL is adopted as a solubilizer to remove the precipitated l-PS from the positive electrode to promote additional electron transfer reactions. The ILs effectively dissolve l-PS and greatly improve the electrochemical performance by allowing greater utilization of l-PS, which results in a higher initial specific capacity, together with a moderate retention rate. The results presented here confirmed that the use of an IL as an additive is quite effective at enhancing the overall performance of the Li-S cell and this understanding will enable the construction of highly efficient Li-S batteries.