A series of sulfated aluminum oxides (S-Al
2
O
3
), investigated as an electrolyte additive in Nafion membranes, was synthesized
via
three different methods: (i) sol–gel sulfation starting from an ...aluminum alkoxide precursor, (ii) room temperature sulfation of fumed aluminum oxide, and (iii) hydrothermal sulfation of fumed aluminum oxide. Through the characterization of the synthesized S-Al
2
O
3
by means of X-ray diffraction (XRD), thermogravimetric analysis (TGA), and infrared (IR) spectroscopy, a higher sulfation rate was found to be achieved
via
a hydrothermal sulfation, and the coordination state of sulfate groups was identified as monodentate. By using this hydrothermally synthesized S-Al
2
O
3
as additive, a composite Nafion-based membrane was realized and compared to plain Nafion, by means of thermal analyses and fuel cell tests. Although higher hydration degree was found for the undoped membrane by differential scanning calorimetry (DSC), improved retention of fuel cell performance upon the increase of operation temperature was observed by using the composite electrolyte, confirming the stabilizing effect of the acidic inorganic additive.
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Suitably selected ionic liquids (ILs) are first applied as antistatic agents for poly(methyl methacrylate) (PMMA) and poly(butyl methacrylate) (PBMA) films in this study. We have ...compared volume- and surface-resistivity (Rv and Rs) on the basis of the morphology of the composite films. These values were found to deeply relate to the compatibility. For pure polymer films, both Rv and Rs were found to be around 1012Ωcm and 1014Ωcm−2, respectively at 60°C. These values were reduced hundred times by adding 10wt% of the ILs having a high compatibility with polymer matrices. When the compatibility is good enough, ILs are uniformly incorporated into the matrices, and accordingly the films are properly plasticized and fully transparent. We also show that the incorporation of ILs, having poor compatibility with polymethacrylates, results in the turbid films with a concomitant reduction of Rs but not of Rv, attributed to the bleed out of the ILs from the films. We believe that assuring the transparency of the film and suppressing undesired washing out effect of ILs are major tasks, and hence, we conclude that ILs showing high affinity with polymethacrylates are the most promising antistatic agents for polymethacrylates.
We demonstrate that the addition of 1-butyl-1-methylpyrrolidinium hexafluorophosphate (Py14PF6) to 1.0 M LiPF6 in ethylene carbonate-dimethyl carbonate (LP30) widens the temperature range, in which ...the electrolyte mixtures are ion conductive and safe. Specifically, at the concentrations of Py14PF6 above 50 wt%, the electrolyte mixtures exhibit a flash point higher than room temperature and fulfill the requirements of liquids having controlled flammability. In this concentration range, also crystallization of the mixtures is completely suppressed, and low temperature ionic conductivity is improved. With respect to the electrochemical properties at room temperature, electrochemical stability window is widened by the addition of Py14PF6 to LP30. However, it comes at the cost of slightly increased overall impedance and overpotential in Li | Li symmetric cells. We utilize these mixed electrolytes in high voltage Li | LiNi0.5Mn1.5O4 cells. In the presence of 30 wt% and 50 wt% of Py14PF6 in LP30, the cells exhibit high specific capacity of about 110 mAh g−1 over 200 cycles and improved coulombic efficiency, suggesting Py14PF6 is a promising additive for the electrolyte in high-voltage, stable and safe lithium batteries.
Mobility of component anions of ionic liquids (ILs) was found to be a most effective factor to enhance antistatic properties of polyether-based polyurethanes (PUs). Then, the antistatic effects were ...discussed with Kamlet-Taft parameters (hydrogen bond acidity: α and basicity: β) of the added ILs. A strong correlation was found between β value and surface resistivity (Rs) of the PUs containing the ILs. On the contrary, α value was found to have a weak influence on the Rs. Since there was a weaker interaction between polyether chains and anions than cations, antistatic effects of the ILs were weaken by fixing the component anions into the PUs. This strongly suggests that effective antistatic effects are supported by the anion migration of ILs.
In this work, the use of
-methyl-
-propylpiperidinium difluoro(oxalato)borate Pip
DFOB ionic liquid (IL), originally synthesized in our laboratory, as an additive for liquid electrolytes in ...lithium-ion batteries (LIBs), is proposed. The synthesized IL exhibits glass and melting transitions at -70.9 °C and 17.1 °C, respectively, and a thermal decomposition temperature over 230 °C. A mixture based on 1.0 M LiPF
in 1:1
/
ethylene carbonate (EC): dimethyl carbonate (DMC) electrolyte solution (so called LP30) and the IL was prepared and tested in lithium metal cells versus two different commercially available carbonaceous electrodes, i.e., graphite (KS6) and graphene (GnP), and versus a high voltage LiNi
Mn
O
(LNMO) cathode. A noticeable improvement was observed for Li|LNMO cells with an IL-added electrolyte, which exhibited a high specific capacity above 120 mAh g
with a Coulombic efficiency above 93% throughout 200 cycles, while the efficiency fell below 80% after 80 cycles with the absence of IL. The results confirm that the IL is promising additive for the electrolyte, especially for a longer cycle life of high-voltage cells.
Here, two ionic liquids, N‐ethoxyethyl‐N‐methylmorpholinium bis(trifluoromethanesulfonyl)imide (M1,2O2TFSI) and N‐ethoxyethyl‐N‐methylpiperidinium bis(trifluoromethanesulfonyl)imide (P1,2O2TFSI) were ...synthesized and compared. Fundamental relevant properties, such as thermal and electrochemical stability, density, and ionic conductivity were analyzed to evaluate the effects caused by the presence of the ether bond in the side chain and/or in the organic cation ring. Upon lithium salt addition, two electrolytes suitable for lithium batteries applications were found. Higher conducting properties of the piperidinium‐based electrolyte resulted in enhanced cycling performances when tested with LiFePO4 (LFP) cathode in lithium cells. When mixing the P1,2O2TFSI/LiTFSI electrolyte with a tailored alkyl carbonate mixture, the cycling performance of both Li and Li–ion cells greatly improved, with prolonged cyclability delivering very stable capacity values, as high as the theoretical one in the case of Li/LFP cell configurations.
A safer electrolyte: A lithium–ion battery, delivering very stable prolonged capacity with 100 % Coulombic efficiency, is proposed by coupling a new ionic liquid‐based electrolyte with Sn/C anode and LiFePO4 cathode.
Organic–inorganic hybrid electrolytes based on Al-doped Li7La3Zr2O12 (LLZO) and two different ionic liquids (ILs), namely N-ethoxyethyl-N-methylpiperidinium bis(fluorosulfonyl)imide (FSI IL) and ...N-ethoxyethyl-N-methylpiperidinium difluoro(oxalato)borate (DFOB IL), were prepared with the aim of improvement of inherent flexibilities of inorganic solid electrolytes. The composites were evaluated in terms of thermal, spectroscopical, and electrochemical properties. In the impedance spectra of LLZO composites with 15 wt% ILs, a semi-circle due to grain boundary resistances was not observed. With the sample merely pressed with 1 ton, without any high-temperature sintering process, the ionic conductivity of 10−3 S cm−1 was achieved at room temperature. Employing a ternary composite of LLZO, FSI IL, and LiFSI as an electrolyte, all-solid-state lithium metal batteries having LiFePO4 as a cathode were assembled. The cell exhibited a capacity above 100 mAh g−1 throughout the course of charge–discharge cycle at C/20. This confirms that FSI IL is an effective additive for inorganic solid electrolytes, which can guarantee the ion conduction.
A safe and environmentally friendly material for corrosion removal from metals is proposed in this article. Electrochemically corroded copper was selected as a target material, and a deep eutectic ...solvent (DES) composed of choline chloride and ascorbic acid, in a molar ratio of 2:1, was developed to this end. Aqueous solutions of the DES with a concentration above 70 wt% were found to be effective in the dissolution of patina and less aggressive towards other materials such as CaCO
which is the main component of limestone. These concentrated DES solutions were integrated with either cotton swabs or cellulose-based membranes and used for the cleaning of electrochemically corroded copper. The membrane containing 80 wt% DES aqueous solution exhibited the most desirable cleaning ability in terms of speed and area selectivity. X-ray diffraction analysis of the corroded copper before and after the application of the membrane was performed to demonstrate the successful corrosion removal.
A study on the interfacial properties between a solid glassy electrolyte, LiI‐Li3PS4 (LPSI), and graphite (MAG) composite electrodes was carried out with the aim of reducing or even eliminating the ...irreversible capacity during the 1st charge‐discharge cycle. The performances of all‐solid‐state MAG|LPSI|Li cells were compared with those of conventional liquid cells. To reinforce a well‐distributed conductive path in MAG as well as at the MAG/LPSI interface, the type of electron conducting additive and the pressure during cell preparation were optimized. Specific functions of the conducting additive were demonstrated, where the sub‐micrometric carbon fibers allowed better galvanostatic performance in the solid‐state configuration by virtue of their high aspect ratio. The coulombic efficiency of solid‐state cells was improved from 46 to 99 % and the reversible capacity value from 100 to 270 mAh g−1, by increasing the pressure from 2 to 4 ton. The interfacial stability of LPSI was also evaluated by impedance spectroscopy of MAG|MAG and Li|Li cells over time. Although ionic resistance of LPSI was higher than a conventional liquid electrolyte, LPSI exhibited controlled interfacial resistance.
Liquid or solid? High interfacial stability of LiI‐Li3PS4 against lithium and graphite anodes was demonstrated by means of impedance spectroscopy and galvanostatic cycling. Moreover, an electron conductive additive in anodes was revealed to have a different role in all‐solid cells compared that in conventional liquid cells.
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