• Carbon letters
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• v.15 no.3
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• pp.187-191
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• 2014

This study reports on the influence of N-butyl-N-methylpyrrolidinium tetrafluoroborate ($PYR_{14}BF_4$) 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 tetraethylammonium tetrafluoroborate ($TEABF_4$) as a common salt. Using the $PYR_{14}BF$ ionic liquid as additive produced higher ionic conductivity in the electrolyte and lower interface resistance between carbon and electrolyte, resulting in improved capacitance. The chemical and electrochemical stability of the electrolyte was measured by ionic conductivity meter and linear sweep voltammetry. The electrochemical analysis between electrolyte and carbon electrode was examined by cyclic voltammetry and electrochemical impedance spectroscopy.

• Carbon letters
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• v.16 no.1
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• pp.51-56
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• 2015

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 ($EMImBF_4$). 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 $EMImBF_4$ content increased the ionic conductivity and reduced bulk resistance and interfacial resistance. In particular, after adding 15 vol% $EMImBF_4$ in 0.2 M $SBPBF_4$ PC/DMC electrolyte, the organic electrolyte showed superior capacitance and interfacial resistance. However, when $EMImBF_4$ content exceeded 15 vol%, the capacitance was saturated and the voltage range decreased.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.466-470
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• 2014

In this paper, organic solvent electrolytes were prepared by a mixture of propylene carbonate (PC), dimethyl carbonate (DMC), tetraethylammonium tetrafluoroborate ($TEABF_4$)s to evaluate the ionic properties of propylene carbonate (PC)/dimethyl carbonate (DMC) mixtures as solvents for a capacitor application, in view of improving the electrochemical performances. The bulk resistance and interfacial resistance of the mixture electrolytes were investigated using an AC impedance method. The morphology of carbon-based electrodes which were contained in different electrolytes was analyzed by scanning electron microscopy (SEM) method. From the experimental results, by increasing the FEC content, capacitance of electrodes was increased, and the interfacial resistance was decreased. In particular, by a content of 2 vol % FEC in 0.2 M $TEABF_4$ PC/DMC solvent, the electrolyte showed the superior capacitance. However, when FEC content exceeds 2 vol %, the capacitance was decreased and the interfacial resistance was increased.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.822-827
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• 1999

The specific capacitance characteristics which were of the electric double layer capacitors(ELDC) made of phenol based activated carbon fiber(ACF) electrodes and organic electrolytes has been investigated with respect to different specific surface area of electrodes and different kinds of organic electrolytes. Throughout charge-discharge cell tests, it has been found that larger surface area and larger pore diameter of electrodes contribute to increase the specific capacitance. Binary mixture of organic solvent with propylene cabonate(PC) and tetrahydrofuran(THF) for 1 M-$LiClO_4$ electrolyte has a higher specific capacitance than single solvent of PC or mixed solvent with PC and diethyl cabonate(DEC). Also, even though 1 M-tetraethylamonium perchlorate(TEAPC) of organic electrolyte shows higher specific capacitance, it has longer charge time because of its lower ion mobility.

• Polymer(Korea)
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• v.31 no.4
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• pp.297-301
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• 2007

In this work, polymer/(layered silicate) nanocomposites (PLSN) based on poly (ethylene oxide) (PEO), ethylene carbonate (EC) as a plasticizer, lithium salt ($LiClO_4$), and sodium montmorillonite ($Na^+-MMT$) or organic montmorillonite (organic MMT) clay were fabricated. And the effects of organic MMT on the polymer matrix were investigated as a function of ionic conductivity. For the application to electrolytes an Li batteries, polymer electrolytes containing the organic nanoclays were used in this work. As a result, the spacing between layers and hydrophobicity of the organic nanoclays were increased, affecting on the exfoliation behaviors of the MMT layers in clay/PEO nanocomposites. From ion-conductivity results, the organic-MMT showed higher values than those of $Na^+-MMT$, and the MMT-20A sample that was treated by methyl dihydrogenated tallow ammonium, showed the highest conductivity in this system.

• Applied Chemistry for Engineering
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• v.32 no.4
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• pp.467-471
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• 2021

A ladder-like polysilsesquioxane (LPMA64) functionalized with a crosslinkable group was synthesized and used for the preparation of organic-inorganic hybrid gel polymer electrolytes through a thermal crosslinking process of the liquid electrolytes. A small weight percent of LPMA64 polymer crosslinker (5 wt%) was able to form a well-developed network structure, resulting in good dimensional stability with high ionic conductivity. The lithium-sulfur batteries fabricated with organic-inorganic hybrid gel polymer electrolytes exhibited stable C-rate and cycling performance with excellent Coulombic efficiency due to the alleviated lithium polysulfide shuttling effect during prolonged cycling. The result demonstrates that the organic-inorganic hybrid gel polymer electrolytes could be a promising candidate electrolyte for application in lithium-sulfur batteries.

• Ceramist
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• v.21 no.4
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• pp.349-365
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• 2018

Since the electrification of vehicles has been extended, solid-state batteries have been attracting a lot of interest because of their superior safety. Especially, polymer, sulfide, and oxide based materials are being studied as solid electrolytes, and each type of materials has advantaged and disadvantages over others. Oxide electrolytes has higher chemical and electrochemical stability compared to the other types of electrolytes. However, ionic conductivity isn't high enough as much as that of organic liquid electrolytes. Also, there are many difficulties of fabricating solid-state batteries with oxide based electrolytes because they require a sintering process at very high temperature (above ${\sim}800^{\circ}C$). Herein, we review recent studies of solid-state batteries with oxide based electrolytes about the ionic conductivity, interfacial reactions with Li metal, and preparation of solid-state cell.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3190-3194
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• 2010

Mixed electrolytes formed by the combination of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (BMP-TFSI) ionic liquid and standard liquid electrolyte are prepared and characterized. Linear sweep voltammetry measurements demonstrate that these mixed systems exhibit a wide electrochemical stability window, allowing them to be suitable electrolyte for carbonaceous anode-based lithium-ion batteries. Lithium-ion cells composed of graphite anode and $LiCoO_2$ cathode are assembled using the mixed electrolytes, and their cycling performances are evaluated. The cell containing proper content of BMP-TFSI shows good cycling performance comparable to that of a cell assembled with organic electrolyte. The presence of BMP-TFSI in the mixed electrolyte contributes to the reduction of the flammability of electrolyte solution and the improvement of the thermal stability of charged $Li_{1-x}CoO_2$ in the electrolyte solution.

• 한국전기화학회:학술대회논문집
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• 2003.07a
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• pp.169-171
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• 2003

Organic/inorganic hybrid membranes have been prepared and evaluated as polymer electrolytes in a polymer electrolyte membrane fuel cell (PEMFC). Previously, partially fluorinated poly (arylenether) was synthesized and the polymer was sulfonated by fuming sulfuric acid$(30\%\;SO_3)$. Modification of these polymers with coupling agent and inorganic materials was carried out to prepare membranes. Membranes cast from these materials were investigated in relation to the proton conductivity and weight loss at the room temperature. It was found that these membranes had a higher conductivity of $10^{-2}\;Scm^{-1}$ at the room temperature. But inorganic materials have leaked out from the hybrid membrane. If this problem is resolved, organic/inorganic hybrid membranes will become satisfactory Polymer electrolytes for the PEMFC.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.295-298
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• 1998

We have investigated ionic conductivity and electrochemical stability of the electrolytes containing organic solvent. Ion conductivities were measured between 10 and 80$^{\circ}C$, and electrochemical stabilities were determined by cyclic voltammetry on glassy carbon, platinum and aluminum electrodes. Ionic conductivity of electrolyte(EC:DEC=1:1) with IM LiPF$\_$6/ shows better than that of the other electrolytes having Li salts. The IM LiBF$_4$-PC electrolyte exhibits good electrochemical stability. IM LiPF$\_$6/ (EC:DEC=1:1) and IM LiPF$\_$6/ (EC:DMC=1:1) electrolytes are used for the high capacity of battery system.