In this study, we synthesized a reduced graphene oxide-manganese dioxide (rGO-MnO2) composite material using a one-step hydrothermal method and used it as a transducer layer in solid-state ion-selective electrodes (ISEs) for monitoring potassium and sodium ions in sweat. The rGO-MnO2 composite was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), revealing its unique surface morphology and crystalline structures. Electrochemical characterizations, including cyclic voltammetry (CV) and potential response testing, demonstrated the excellent performance of the rGO-MnO2 composite material as a transducer layer in ISEs. The fabricated electrodes displayed good linear responses to potassium and sodium ions, with a voltage response of 36.4 mV and 47.6 mV per unit concentration change, respectively. The electrodes also exhibited improved resistance to gas interference, such as O2, N2, and CO2. We utilized these ISEs to measure changes in potassium and sodium ion concentrations in sweat samples collected over nine days of exercise, demonstrating the practical application of the rGO-MnO2-based ISEs. This work highlights the potential of using graphene/metal oxide composites as solid contact materials in ISEs for cost-effective and stable ion sensing applications.

To study the effect of inorganic electrolyte solution on graphite flotation, 19 kinds of inorganic electrolytes, including nitrate, chloride and sulfate were selected as experimental electrolytes. The flotation experiment was carried out on graphite and the contact angle and surface potential of the interaction between inorganic electrolyte solution and graphite were studied. The results show that flotation effect and flotation rate of the three ion valence inorganic electrolytes follow the order: nitrate < chloride < sulfate and univalent < bivalent < trivalent (except Ba(NO3)2 and Pb(NO3)2). When the ion valence are the same, the larger the ion atomic number, the better effect on graphite flotation. Cations in inorganic electrolyte solutions are the main factors affecting mineral flotation. When the cationic type and concentration are the same, different flotation effects are attributed to different anions. For low ion valence inorganic electrolyte solution with weak foaming effect, a certain dose of frother can be added appropriately to improve the flotation effect of graphite. The high ion valence inorganic electrolyte solution has strong foaming effect, and it is not necessary to add a frother. The principle of inorganic electrolyte solution promoting graphite flotation is analyzed from the aspects of liquid phase property, gas–liquid interface property, contact angle and surface potential. It is proved that inorganic electrolyte solution as flotation medium can promote the effective flotation of graphite.

Flexible zinc-air batteries have many merits, including low cost, high safety, environmentally friendliness applicability, etc. One of the key factors to improve the performance of flexible zinc-air batteries is to use a gel electrolyte. In this study, gel electrolytes were synthesized from potato, sweet potato, and corn starch. In a comparison of each starch, the corn starch-based gel electrolyte showed the highest discharge capacity of 12.41 mAh/cm2 in 20 mA and 6.47 mAh/cm2 in 30 mA. It also delivered a higher specific discharge capacity of 7.06 mAh/cm2 than the other materials after 100° bending. In addition, the electrochemical impedance spectroscopy (EIS) was analyzed to calculate the ionic conductivity. The potato, sweet potato, and corn starch-based gel electrolytes showed electrolyte resistances (Re) of 0.306, 0.298, and 0.207 Ω, respectively. In addition, the corn starch-based gel electrolyte delivered the highest ionic conductivity of 0.121 S cm-1 among the other gel electrolytes. Thus, the corn starch-based gel electrolyte was verified to improve the performance of flexible zinc-air batteries

An electrical double-layer capacitor is fabricated with biomass-derived activated carbon (AC) and multi-walled carbon nanotubes (MWCNTs), which are synthesized from Pongamia pinnata fruit shell and its seed oil, respectively. The activated carbon is produced by the chemical activation process at varying carbonization temperatures from 600 to 900 °C for 5 h at a rate of 10 min in an N2 atmosphere. The surface area of activated carbon and MWCNTs is 1170 m2 g− 1 and 216 m2 g− 1, respectively. The total pore volumes of activated carbon and MWCNTs are 1.51 cm3 g− 1 and 0.5907 cm3 g− 1, respectively. The as-prepared AC and MWCNTs are characterized by surface area analysis Brunner–Emmett–Teller method (BET), X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopic analysis, field emission scanning electron microscopy, high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy. The electrochemical performances of AC-AC, MWCNTs-MWCNTs and AC-MWCNTs (25:75) symmetric electrodes are studied by cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy. The AC-MWCNTs (25:75) single electrode performance is also studied in two different electrolytes, such as 0.5 M Na2SO4 and 0.5 M H2SO4. The fabricated AC-MWCNTs (25:75) symmetric supercapacitor cell exhibits excellent electrochemical performance in 0.5 M Na2SO4. It shows a specific capacitance of 55.51 Fg− 1, energy density 4.852 Wh Kg− 1 and power density of 199.18 W Kg− 1 at a current density of 1 Ag− 1 in the voltage window of 0–1.8 V. The AC-AC and AC-MWCNTs (25:75) symmetric supercapacitor electrodes show outstanding performance.

The energy demands of the world have been accelerating drastically because of the technological development, population growth and changing in living conditions for a couple of decades. A number of different techniques, such as batteries and capacitors, were developed in the past to meet the demands, but the gap, especially in energy storage, has been increasing substantially. Among the other energy storage devices, supercapacitors have been advancing rapidly to fill the gap between conventional capacitors and rechargeable batteries. In this study, natural resources such as pistachio and acorn shells were used to produce the activated carbons for electrode applications in a supercapacitor (or an electrical double-layer capacitor— EDLC). The activated carbon was synthesized at two different temperatures of 700 °C and 900 °C to study its effect on porosity and performance in the supercapacitor. The morphology of the activated carbon was studied using scanning electron microscopy (SEM). A solution of tetraethylammonium tetrafluoroborate ( TEABF4)/propylene carbonate (PC) was prepared to utilize in supercapacitor manufacturing. The performance of the EDLC was investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy. Activated carbons from both the pistachio and acorn shells synthesized at 700 °C in argon gas for two hours exhibited better surface textures and porosity. There activated carbons also exhibited more capacitor-like behavior and lower real impedances, indicating that they would have superior performance compared to the activated carbons obtained at 900 °C. This study may be used to integrate some of natural resources into high-tech energy storage applications for sustainable developments.

본 연구는 1M Li2SO4 및 1M Na2SO4 수용액에서 CoSe 나노 입자의 전기 화학적 성능을 조사 하였다. CoSe 나노 입자의 전기 화학적 효율은 1M Na2SO4 전해질에서 더 높은 비정전 용량을 보여주는 결 과를 얻었고 이것은 주로 1M Na2SO4 용액의 벌크 전해질에서 수화 된 이온의 빠른 이동과 활물질에 의해 제공되는 낮은 전기 화학적 임피던스가 원인이라 사료된다. 또한, 순환 전압 전류법 안정성 실험에서 25 mV s-1의 스캔 속도로 1000 회 연속 순환 전압 전류 측정주기 후에도 각각 1M Na2SO4 및 1M Li2SO4에서 약 92 % 및 89 %의 특정 정전 용량의 유지를 보여주었다. 이 연구는 새로운 하이브리드 슈퍼 커패시터를 개발하기 위한 기초 데이터를 제공하며 비대칭 슈퍼 커패시터의 양극으로 사용될 수 있음을 시사한다.

Supercapacitors are attracting much attention in sensor, military and space applications due to their excellent thermal stability and non-explosion. The ionic liquid is more thermally stable than other electrolytes and can be used as a high temperature electrolyte, but it is not easy to realize a high temperature energy device because the separator shrinks at high temperature. Here, we report a study on electrochemical supercapacitors using a composite electrolyte film that does not require a separator. The composite electrolyte is composed of thermoplastic polyurethane, ionic liquid and fumed silica nanoparticles, and it acts as a separator as well as an electrolyte. The silica nanoparticles at the optimum mass concentration of 4wt% increase the ionic conductivity of the composite electrolyte and shows a low interfacial resistance. The 5 wt% polyurethane in the composite electrolyte exhibits excellent electrochemical properties. At 175 ℃, the capacitance of the supercapacitor using our free standing composite electrolyte is 220 F/g, which is 25 times higher than that at room temperature. This study has many potential applications in the electrolyte of next generation energy storage devices.

This study was performed to analyze a saltiness enhancement at the same salt content through multiple emulsion. We compared the samples with different conditions to determine the optimum stability conditions of water-in-oil through layer separation rate, microscopic observation and size analysis. Four electrolytes such as NaCl, KCl, MgCl2, and CaCl2 were used and agar contents ranged from 0 to 1% were experimented at different volume ratios including 5:5, 4:6, 3:7, 2:8, and 1:9 of water and oil. As a result of this study, the droplet size according to the electrolyte type did not show significant differences (p<0.05). Therefore, KCl was used to facilitate in-body excretion of NaCl in the outer water phase, and corn oil containing 8%(w/w) polyglycerol polyricinoleate was used as oil phase. When the volume ratio of water and oil was 3:7, 2:8, and 1:9, the layer separation rate was relatively slow and droplet size was also small. It reveals that the particle size becomes smaller as the water volume ratio decreases. However, considering the amount of water to be stored and eluted on the inner water, appropriate volume ratio of water and oil should be adopted to 3: 7. At Microscopic observation depending on agar concentrations, small particle size appeared at 0.2% and 0.4% agars. When the water and oil ratio was fixed at 3:7, the particle size was measured at 0.2% and 0.4% agar using a zeta sizer. In conclusion, the droplet size of 0.2% agar was smaller than 0.4%. Therefore, the most stable water-in-oil emulsion was obtained with 0.2% agar, when water to oil ratio was 3:7.

Sulphonated polysulphone (SPS) has been synthesized and subsequently applied as binder for graphene oxide (GO)-based electrodes for development of electrochemical supercapacitors. Electrochemical performance of the electrode was investigated using cyclic voltammetry in 1M Na2SO4 and 1M KOH solution. The fabricated supercapacitors gave a specific capacitance of 161.6 and 216.8 F/g with 215.4 W/kg and 450 W/kg of power density, in 1M Na2SO4 and 1M KOH solutions, respectively. This suggests that KOH is a better electrolyte than Na2SO4 for studying the electrochemical behavior of electroactive material, and also suggests SPS is a good binder for fabrication of a GO based electrode.

본 총설에서는 고분자와 은염으로 구성된 고분자 전해질 분리막과 장시간 안정성을 해결하기 위한 방안들이 정리 되었다. 특히 이온성 액체를 활용하여 AgNO3를 새로운 운반체로 사용하기 위한 방안, 새로운 고분자 매트릭스로서 poly(ethylene phthalate) (PEP)를 활용하는 방안과 가장 최근 알루미늄 염을 활용하여 운반체의 안정성을 부여하는 연구결과들이 정 리되었다. 올레핀 촉진수송을 위한 고분자 나노복합체 분리막의 경우, 운반체인 은 나노입자 표면을 극성화시킬 수 있는 전자 수용체의 종류와 특징들이 소개되었으며, 최근 투과도 성능을 향상시킬 수 있는 연구결과들이 정리되었다.

본 연구는 고온 환경에서 Yorkshire 품종의 혈액 내 전해질과 혈액학적 성분의 변화를 조사하기 위하여 실시하였다. 73 일령(BW 40.6±1.4 kg)의 Yorkshire종 10두를 공시하여 개별 pen에 1두씩 배치하였다. 시험기간은 한국에서 폭염이 시작되는 2013년 7월 24일부터 동년 9월 4일까지 6주간 실시하였다. 시험기간 중 평균온도가 가장 높은 시기는 시험 3주차(28.6℃)였으며, 최고온도는 시험 4주(32.1℃)에 관찰되었다. 일당증체량은 온도가 가장 높았던 시험 3주차부터 감소하는 경향으로 나타났다. 혈청 내 pH와 삼투압은 시험기간 동안 유의적인 변화가 관찰되지 않았다. 나트륨이온 (P<0.01)과 염소이온(P<0.05)의 농도는 시험 6주에 유의적으로 증가하였다. 일반혈액검사 분석 결과에서 혈액 내 호중구(P<0.05)와 단핵구(P=0.057)의 수준은 시험 6주에 증가하고, 헤모글로빈과 평균 적혈구 혈색소 농도는 시험 4주와 6주에 감소하는 것으로 관찰되었다(P<0.05). 혈액생화학 분석에서는 총 콜레스테롤(P<0.01), 총 단백질(P<0.001)과 혈중 요소태 질소(P<0.01)의 농도가 4주와 6주에 높아지는 것으로 관찰되었으며, glucose 농도는 6주에 유의적으로 낮아졌다(P<0.05). 본 연구의 결과는 한국의 여름철 폭염기간 동안 돼지의 체내에서 생리생화학적, 혈액학적 변화가 어떻게 변하는지에 대한 기초정보를 제시하며, 이러한 정보는 혹서기 고온 스트레스로 인한 돼지 생산성저하 방지 기술을 개발하는 데에 기초자료로 활용될 수 있을 것으로 사료된다.

Carbonate-type organic electrolytes were prepared using propylene carbonate (PC) and dimethyl carbonate (DMC) as a solvent, quaternary ammonium salts, and by adding different contents of 1-ethyl-3-methyl imidazolium tetrafluoroborate (EMImBF4). Cyclic voltammetry and linear sweep voltammetry were performed to analyze conducting behaviors. The surface characterizations were analyzed by scanning electron microscopy method and X-ray photoelectron spectroscopy. From the experimental results, increasing the EMImBF4 content increased the ionic conductivity and reduced bulk resistance and interfacial resistance. In particular, after adding 15 vol% EMImBF4 in 0.2 M SBPBF4 PC/DMC electrolyte, the organic electrolyte showed superior capacitance and interfacial resistance. However, when EMImBF4 content exceeded 15 vol%, the capacitance was saturated and the voltage range decreased.

This study reports on the influenceof N-butyl-N-methylpyrrolidinium tetrafluoroborat (PYR14BF4) ionic liquid additive on the conducting and interfacial properties of organic solvent based electrolytes against a carbon electrode. We used the mixture of ethylene carbonate/dimethoxyethane (1:1) as an organic solvent electrolyte and tetraethylammo-nium tetrafluoroborate(TEABF4) as a common salt. Using the PYR14BF ionic liquid as additive produced higher ionic conductivity in the electrolyte and lower interface resis-tance between carbon and electrolyte, resulting in improved capacitance. The chemical and electrochemical stability of the electrolyte was measured by ionic conductivity me-ter and linear sweep voltammetry. The electrochemical analysis between electrolyte and carbon electrode was examined by cyclic voltammetry and electrochemical impedance spectroscopy.

Composites of gadolinium-doped ceria/magnesia(CGO/MgO) were synthesized and characterized for the electrolytes of intermediate temperature solid oxide fuel cells. XRD and SEM results revealed that composite electrolytes consisted of their own phases after sintering at 1400˚C without noticeable solid solution of Mg into CGO. As the MgO content increased, the total electrical conductivity decreased, which might be attributed to the decrease of grain boundary conductivity, possibly due to the lowering of the continuity of the CGO grains and blocking effects of the insulating MgO phase. The space charge effect may not be a significant factor to affect the electrical conductivity of the CGO/MgO composites.

The purpose of this study is to characterize various electrolytes on electrochemical mechanical planarization (ECMP). The ECMP system was modified from conventional CMP system to measure the potentiodynamic curve and removal rate of Cu. The potentiodynamic curves were measured in static and dynamic states in investigated electrolytes using a potentiostat for the evaluation of the polishing behavior on ECMP. KOH (alkaline) and NaNO3 (salt) were selected as electrolytes which have high conductivity. In static and dynamic states, the corrosion potential decreased and the corrosion current increased as a function of the electrolyte concentration. But, the electrochemical reaction was prevented by mechanical polishing effect in the dynamic state. The static etch and removal rate were measured as functions of concentration and applied voltage. When NaNO3 was used, the dissolution was much faster than that of KOH. It was concluded that the removal rate was strongly depended on electrochemical dissolution. The removal rate increased up to 350 nm/min in NaNO3 based electrolyte.

본 연구에서는 SEBS와 여러 가지의 유기화물로 처리된 MMT type의 clay를 이용하여 SSEBS-clay 하이브리드 막을 용액법으로 제조하였다. clay의 함량은 5 phr로 고정하였다. 용액법을 사용하여 clay를 SEBS에 분산시켰으며, 제조된 SSEBS-clay 하이브리드에서 clay의 특성피크가 완전히 박리되거나 이동하는 XRD 결과로부터 고분자의 clay 층간삽입을 확인하였다. Clay의 종류에 따라서 제조된 SSEBS-clay 하이브리드 막의 가스투과도, 기계적 물성 및 열적 성질을 측정하였다. SSEBS-clay 하이브리드 막은 clay 자체의 도입과 층간거리의 확대로 기체분자의 tortuosity를 증가시켜서 가스투과도를 저하시키는 것을 확인하였다.