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1.
Andrzej Lewandowski Agnieszka Swiderska-Mocek 《Journal of Applied Electrochemistry》2010,40(3):515-524
Impedance spectroscopy studies of the interface between lithium and ionic liquid (IL) showed the formation of a film (solid
electrolyte interface, SEI), protecting metal from its further dissolution. Consequently, the potential of metallic lithium
immersed in an electrolyte containing Li+ cations may be described as a Li|SEI|Li+ system, rather than simply Li/Li+. The potential of lithium-metal in a series of ionic liquids (and in a number of molecular liquids) containing Li+ cation (0.1 M) was measured versus the Ag|(Ag+ 0.01 M, cryptand 222 0.1 M, in acetonitrile) reference. The lithium-metal potential (E(Li|SEI|Li+)) was ca. −2.633 ± 0.017 V in ILs based on the [N(CF3SO2)2
–
] anion, while −2.848 ± 0.043 V in ILs containing [BF4
–
] anion (the difference is ca. 200 mV). In the case of ILs based on the triflate anion ([CF3SO3
–
]), the cation of ionic liquid also influences the E(Li|SEI|Li+) value: it was ca. −1.987 ± 0.075 V for imidazolium based cations and much lower (−2.855 V) for the pyrrolidinium based cation.
In ionic liquid based on the imidazolium cation and hexafluorophosphate anion ([PF6
–
]), the Li/SEI/Li+ potential was −2.245 V. The Li|SEI|Li+ potential measured in cyclic carbonates was −2.780 ± 0.069 V while in dimethylsulfoxide showed the lowest value of ca. −3.285 V.
The measured potentials were also expressed versus the formal potential of the ferrocene/ferrocinium redox couple, obtained
from cyclic voltammetry. 相似文献
2.
Effect of additives in PEO/PAA/PMAA composite solid polymer electrolytes on the ionic conductivity and Li ion battery performance 总被引:1,自引:0,他引:1
Sang Yong An Il Chen Jeong Mi-Sook Won Euh Duck Jeong Yoon-Bo Shim 《Journal of Applied Electrochemistry》2009,39(9):1573-1578
Polyethylene oxide (PEO) based-solid polymer electrolytes were prepared with low weight polymers bearing carboxylic acid groups
added onto the polymer backbone, and the variation of the conductivity and performance of the resulting Li ion battery system
was examined. The composite solid polymer electrolytes (CSPEs) were composed of PEO, LiClO4, PAA (polyacrylic acid), PMAA (polymethacrylic acid), and Al2O3. The addition of additives to the PEO matrix enhanced the ionic conductivities of the electrolyte. The composite electrolyte
composed of PEO:LiClO4:PAA/PMAA/Li0.3 exhibited a low polarization resistance of 881.5 ohms in its impedance spectra, while the PEO:LiClO4 film showed a high value of 4,592 ohms. The highest ionic conductivity of 9.87 × 10−4 S cm−1 was attained for the electrolyte composed of PEO:LiClO4:PAA/PMAA/Li0.3 at 20 °C. The cyclic voltammogram of Li+ recorded for the cell consisting of the PEO:LiClO4:PAA/PMAA/Li0.3:Al2O3 composite electrolyte exhibited the same diffusion process as that obtained with an ultra-microelectrode. Based on this electrolyte,
the applicability of the solid polymer electrolytes to lithium batteries was examined for an Li/SPE/LiNi0.5Co0.5O2 cell. 相似文献
3.
Andrzej Lewandowski Ilona Acznik Agnieszka Swiderska-Mocek 《Journal of Applied Electrochemistry》2010,40(9):1619-1624
Ternary [Li+][MePrPip+][NTf2−] and [Li+][MePrPyrr+][NTf2−] room temperature ionic liquids (ILs) were obtained by dissolution of solid lithium bis(trifluoromethanesulfonyl)imide (LiNTf2) in liquid N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide and N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, respectively, and studied as electrolytes for the use in Li/LiFePO4 or C(Li)/LiFePO4 batteries. The cell worked properly in the presence of 10 wt% of vinylene carbonate (VC). Impedance-spectroscopy studies
showed that the additive (VC) forms a protective coating on the anode. The LiFePO4 cathode shows good efficiency (135 mAh g−1) working together with [Li+][MePrPip+][NTf2−] + VC and [Li+][MePrPyrr+][NTf2−] + VC ionic liquid electrolytes. The flash point of ionic liquid electrolytes containing 10 wt% of VC is above 300 °C, which
makes them practically non-flammable. 相似文献
4.
Delwar Hossain Frank Hagelberg Svein Saebo Charles U. PittmanJr. 《Journal of Inorganic and Organometallic Polymers and Materials》2010,20(3):424-444
The structures of endohedral complexes of the polyhedral oligomeric silsesquioxane (POSS) cage molecule (HSiO3/2)12, with both D
2d
and D
6h
starting cage symmetries, containing the atomic or ionic species: Li0, Li+, Li−, Na0, Na+, Na−, K0, K+, K−, F−, Cl−, Br−, He, Ne, Ar were optimized by density functional theory using B3LYP and the 6-311G(d,p) and 6-311 ++G(2d,2p) basis sets.
The exohedral Li+, Na+, K+, K−, F−, Cl−, Br−, He, Ne, Ar complexes, were also optimized. The properties of these complexes depend on the nature of the species encapsulated
in, or bound to, the (HSiO3/2)12 cage. Noble gas (He, Ne and Ar) encapsulation in (HSiO3/2)12 has almost no effect on the cage geometry. Alkali metal cation encapsulation, in contrast, exhibits attractive interactions
with cage oxygen atoms, leading to cage shrinkage. Halide ion encapsulation expands the cage. The endohedral X@(HSiO3/2)12 (X = Li+, Na+, K+, F−, Cl−, Br−, He and Ne) complexes form exothermically from the isolated species. The very low ionization potentials of endohedral Li0, Na0, K0 complexes suggest that they behave like “superalkalis”. Several endohedral complexes with small guests appear to be viable
synthetic targets. The D
2d
symmetry of the empty cage was the minimum energy structure in accord with experiment. An exohedral fluoride penetrates the
D
6h
cage to form the endohedral complex without a barrier. 相似文献
5.
Kenzo Inoue Tatsuya Yamauchi Tomomichi Itoh Eiji Ihara 《Journal of Inorganic and Organometallic Polymers and Materials》2007,17(2):367-375
The role of cyclophosphazenes with oxyethylene chains (N3P3(OCH2CH2)nOCH3, (n = 3, 3, n = 7.2, 4) and N4P4[OC6H4O(CH2CH2O)7.2CH3]8 (8) for the synthesis and ionic conductivity in polymethacrylate networks was studied. Reflecting the structural features of
cyclophosphazenes, the 7Li NMR spectra of the mixture of 3 and LiN(SO2CF3)2 showed that more than 40% of the Li+ salt could exist as a free ion at room temperature. Similar values were obtained for 4 and 8. Cross-linked methacrylate polymers (12–14, and 16–18) were prepared from the reaction of poly(ethylene glycol) methyl ether methacrylate and poly(ethylene glycol) dimethacrylate
both in the presence of these cyclophosphazenes which act as molecular imprinting molecules (method II, M-II) and without
the cyclophosphazene (method I) DSC studies of the imprinted polymer, 12(20)/3/Li+ system after removal of the cyclophosphazene showed that the glass transition temperature range (ΔTg) becomes significantly narrower compared to that of the unimprinted 11(20)/3/Li+ system, where cross-linked polymer 11(20) was prepared in the absence of the cyclophosphazenes (method I, M-I). The ionic conductivity of the Li+/cross-linked polymer system was improved by the subsequent readdition of the cyclophosphazenes. The 12(20)/3/Li+ complex showed a conductivity of 1.1 × 10−3 S/cm at 90 °C, which was two times higher than that of the 11(20)/3/Li+ complex. The effectiveness of the small molecule imprinting technique for the preparation of cross-linked polyelectrolytes
with high conductivity and mechanical stability is discussed.
We dedicate this paper to Professor Christopher W. Allen for his creative, pioneering work in inorganic ring and inorganic-organic
hybrid polymers. 相似文献
6.
A series of well-ordered lamellar mesoporous molybdenum oxides were prepared using gemini surfactant [C
n
H2n+1N+(CH3)2–(CH2)2–N+(CH3)2C
n
H2n+1] · 2Br−(denoted as C
n-2-n
, n = 12, 14 and 16) as the structure-directing agent and ammonium heptamolybdate tetrahydrate (NH4)6Mo7O24 · 4H2O as the precursor. The obtained samples were characterized by X-ray powder diffraction, thermal analysis, transmission electron
microscopy and nitrogen adsorption–desorption. Results showed that contrary to complete structure collapse after removing
tetradecyltrimethylammonium bromide (TTAB) from molybdenum oxide/TTAB composite, the lamellar mesostructure was retained after
removal of C
n-2-n
from corresponding composite. The effects of alkyl chain length and concentration of gemini surfactants on the structure
of the mesoporous molybdenum oxide were also investigated. The specific surface area of extracted sample was as high as 116 m2 g−1. The maintenance of the lamellar mesostruture was due to the strong self-assembly ability of gemini surfactants and the strong
electrical interaction between gemini surfactants and molybdenum oxide. 相似文献
7.
A new type of lithium salts, —SO2NLiSO2OCH2(CF2)nCH2Om— (LiPPFASI, where n = 2, 3, 4, 6, and 7), was used as salts in poly(ethylene oxide) (PEO)‐based solvent‐free electrolytes. The conductivity and electrochemical stability behaviors were studied. The results showed the electrolytes almost have a similar conductivity and the PEO–LiPPFASI (n = 3, EO/Li = 10) was the relatively better system under the experiment conditions. Moreover, most systems were found to be oxidatively stable up to 5.5 V versus Li/Li+ and the lithium deposition‐stripping process on the electrode was reversible for all the polymer electrolytes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1882–1885, 2001 相似文献
8.
Li ion conducting polymer electrolyte films were prepared based on poly(vinyl alcohol) (PVA) with 5, 10, 15, 20, 25 and 30 wt%
lithium iron phosphate (LiFePO4) salt using a solution-casting technique. X-ray diffraction (XRD) was used to determine the complexation of the polymer with
LiFePO4 salt. Differential scanning (DSC) calorimetry was used to determine the melting temperatures of the pure PVA and complexed
films. The maximum ionic conductivity was found to be 1.18 × 10−5 S cm−1 for (PVA:LiFePO4) (75:25) film, which increased to 3.12 × 10−5 S cm−1 upon the addition of propylene carbonate (PC) plasticizer at ambient temperature. The Li+ ion transport number was found to be 0.40 for (PVA: LiFePO4) (75:25) film using AC impedance and DC polarization methods. Dielectric studies were performed for these polymer electrolyte
films in the frequency range of 10 Hz to 10 MHz at different temperatures. The activation energies of the complexed films
were calculated from the dielectric loss tangent spectra and were found to be 0.35, 0.30, 0.27 and 0.28 eV. The cyclic voltammogram
(CV) curves of (PVA: LiFePO4) (75:25)+PC film exhibited higher specific capacities than those for other films. 相似文献
9.
Hong-Bo Han Shao-Wei Feng Wen-Fang Feng Jin Nie Hong Li Hajime Matsumoto Zhi-Bin Zhou 《Electrochimica acta》2010,55(23):7134-10666
New functionalized ionic liquids (ILs), comprised of multi-methoxyethyl substituted quaternary ammonium cations (i.e. [N(CH2CH2OCH3)4−n(R)n]+; n = 1, R = CH3OCH2CH2; n = 1, R = CH3, CH2CH3; n = 2, R = CH3CH2), and two representative perfluorinated sulfonimide anions (i.e. bis(fluorosulfonyl)imide (FSI−) and bis(trifluoromethanesulfonyl)imide (TFSI−)), were prepared. Their fundamental properties, including phase transition, thermal stability, viscosity, density, specific conductivity and electrochemical window, were extensively characterized. These multi-ether functionalized ionic liquids exhibit good capability of dissolving lithium salts. Their binary electrolytes containing high concentration of the corresponding lithium salt ([Li+] >1.6 mol kg−1) show Li+ ion transference number (tLi+) as high as 0.6-0.7. Their electrochemical stability allows Li deposition/stripping realized at room temperature. The desired properties of these multi-ether functionalized ionic liquids make them potential electrolytes for Li (or Li-ion) batteries. 相似文献
10.
Summary The new single ion conductors, poly(oligo-oxyethylene methacrylate-co-alkali metal acrylamidocaproic acid) ((CH2CCH3COO(CH2CH2O)9H)x–(CH2CHCONH(CH2)5 COO-M+)1-x), M+=Li+, Na+, K+, were synthesized and the effects of the cation and the temperature on ionic conductivity were investigated. The alkyl spacer in the alkali metal acrylamidocaproate was introduced to increase the flexibility of the side chain for the complex formation between the ionic groups and the oxygens in PEO unit. The room temperature(30°C) conductivity of the K single ion conductor was found to be 5x10-7 S/cm which is the highest value reported for the single ion conductors having carboxylate groups without any additives. The pseudo-activation energy in the VTF equation was not dependent on the type of the cation, which indicates that the ion hopping rate is higher than the string renewal rate in these single ion conductors. 相似文献
11.
The electrochemical properties of amorphous vanadium pentoxide (V2O5) thin films deposited by reactive r.f.-sputtering were investigated using galvanostatic charge/discharge cycling and galvanostatic
intermittent titration technique (GITT). As x in Li
x
V2O5−y
increased (x = 0–2.0), the electromotive force of the lithium (Li)∣1 M LiClO4–propylene carbonate∣Li
x
V2O5−y
cell decreased gradually without a potential plateau or an abrupt potential reduction, demonstrating that an irreversible
structural change did not occur in the entire Li content. Chemical diffusivity of the Li ion in the Li
x
V2O5−y
thin film measured using GITT was determined to be 4 × 10−13–7 × 10−14 cm2 s−1 in the Li content range investigated. 相似文献
12.
Fast atom bombardment (FAB) desorption of phosphatidylserine and various phosphatidylcholines produces a limited number of
very informative negative ions. Especially significant is the formation of (M-H)− ions for phosphatidylserine, a compound which does not yield informative high mass ions by other ionization methods. Phosphatidylcholines
of not yield (M-H)− ions but instead produce three characteristic high mass ions, (M-CH
3
+
_−, [M-HN(CH3)
3
+
]− and [M-HN(CH3
3
+
-C2H2]−. Both classes of lipids also yield anions attributed to the carboxylate components of these complex lipids. FAB desorption
in combination with collisional activation allows for characterization of fragmentation and determination of structural features.
Collisional activation of the carboxylate anion fragments from the complex lipids is especially informative. Structural characterization
of the fatty acid chain can be achieved as the released saturated carboxylate anions undergo a highly specific 1,4-elimination
of H2, which results in the losses of the elements of CH4, C2H6, C3H8...in a fashion entirely consistent with the chemistry of carboxylate anions desorbed from free fatty acids. These CnH2n+2 losses begin at the alkyl terminus and progress along the entire alkyl chain. Modified fatty acids undergo a similar fragmentation;
however, the modification affects the series of CnH2n+2 losses in a manner which permits determining the type of modification and its location on the fatty acid chain. 相似文献
13.
The fluoride-catalysed hydrolysis of mixtures of CH3Si(OCH3)3 and Mg(OC2H5)2 in the presence of preformed nanosized R4N+Br−-stabilised Pd colloids results in the formation of micro/mesoporous hydrophobic sol–gel materials in which the Pd clusters
are entrapped individually in the solid matrix. The materials are active catalysts in the hydrogenation of 1,5-cyclooctadiene.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
The mode of action of the lithium ion (Li+) in the treatment of manic depression or bipolar illness is still under investigation, although this inorganic drug has been
in clinical use for 50 yr. Several research reports have provided evidence for Li+/Mg2+ competition in biomolecules. We carried out this study to characterize the interactions of Li+ and Mg2+ with red blood cell (RBC) membrane components to see whether Li+/Mg2+ competition occurs. 31P nuclear magnetic resonance chemical shift measurements of the phospholipids extracted from the RBC membranes indicated that
the anionic phospholipids, phosphatidylserine and phosphatidylinositol, bind Li+ and Mg2+ most strongly. From 6Li relaxation measurements, the Li+ binding constant to the phospholipid extract was found to be 45±5M−1. Thus, these studies showed that the phospholipids play a major role in metal ion binding. 7Li spin-lattice relaxation measurements conducted on unsealed and cytoskeleton-depleted RBC membrane in the presence of magnesium
indicated that the removal of the cytoskeleton increases lithium binding to the more exposed anionic phospholipids (357±24
M−1) when compared to lithium binding in the unsealed RBC membrane (221±21 M−1). Therefore, it can be seen that the cytoskeleton does not play a major role in Li+ binding or in Li+/Mg2+ competition. 相似文献
15.
José E. Báez Ángel Marcos-Fernández Plácido Galindo-Iranzo 《Journal of Polymer Research》2011,18(5):1137-1146
Poly(L-lactide) (PLLA) oligo-esters with α-hydroxyl-ω-alkyl (alkyl = −CH2−[CH2−CH2]m−CH3, where m = 1, 2, 4, 5, 6, 7, 8, 9, and 10) end groups were synthesized by ring-opening polymerization of L-lactide (L-LA)
catalyzed by tin(II) 2-ethylhexanoate Sn(Oct)2 in the presence of aliphatic alcohols as initiators (HO−CH2−[CH2−CH2]m−CH3, where m = 1, 2, 4, 5, 6, 7, 8, 9, and 10). High yields (~ 62 to 71%) and M
n(NMR) in the range of 2120–2450 Da (PLLA) were obtained. Effects of alkyl end groups on thermal properties of the oligo-esters
were analyzed by DSC, TGA and SAXS. Glass transition temperature (T
g) gradually decreases with increase in the percent of−CH2−[CH2−CH2]m−CH3 end group, as results alkyl end group provides most flexibility to PLLA. An important effect of alkyl end group on a double
cold crystallization (T
c1 and T
c2) was observed, and is directly related with the segregation phase between alkyl end group and PLLA. TGA analysis revealed
that PLLA oligo-esters are more thermally stable with docosyl (−C22H45) respect to the butyl (−C4H9) end group, probably is due to steric hindrance of the end group (docosyl respect to butyl) toward intermolecular and intramolecular
transesterification. SAXS analysis showed that alkyl end group as docosyl restricted the growth of lamellae thickness (D)
due to steric hindrance. Characterization of hydroxyl and alkyl end groups in the PLLA oligo-esters was determined by MALDI-TOF,
GPC, FT-IR and 1 H and 13 C NMR. 相似文献
16.
Surface and aqueous properties of anionic gemini surfactants having dialkyl amide,carboxyl, and carboxylate groups 总被引:1,自引:0,他引:1
A systematic study of the equilibrium surface properties (in water and in the presence of 10−2 M NaCl) of a novel series of anionic gemini surfactants, (CH2)2[N(COCnH2n+1)CH(COOH)CH2COOH]·2NaOH (GA), where (n+1)=8, 10, 12, 14, and 16, was investigated. The responses of humans to closed patch tests with
(CH2)2[N(COC11H23)CH(COOH)−CH2COOH]2·2NaOH (GA-12) were also investigated. Premicellar self-aggregation (both in water and 10−2 M NaCl) occurred when the N-acyl group contained more than 14 carbon atoms, since the critical micelle concentration (CMC) values decreased and the pC20 values increased as (n+1) increased for (n+1) ≤14; the CMC values increased and the pC
20 values decreased as (n+1) increased for (n+1)>14, both in water and in 10−2 M NaCl. The absence of a break in the specific conductance-surfactant molar concentration plots for the GA homologs indicates
protonation of the carboxylate group and strong Na+ release during micellization. This is a structural characteristic of the anionic geminis having N-dialkylamide and carboxylate groups in a molecule. The skin irritation potential of GA-12 is lower than that of the corresponding
“monomer”, C11H23CON(CH3)CH(COOH)CH2(COOH)·NaOH, and the analog, C11H23CON(CH3)CH2COONa·H2O. 相似文献
17.
Amal A. Hafiz A. M. Badawi F. I. El-Deeb E. A. Soliman M. Y. El-Awady D. E. Mohamed 《Journal of surfactants and detergents》2010,13(2):165-172
A novel series of ferrocenyl surfactants was synthesized by the reaction of ferrocene disulfonic acid with different primary
and tertiary fatty amines to produce the corresponding ammonium salts Fc[SO3
−
+NH3(CH2)
n
CH3]2, where n = 9, 11, or 15 and Fc[SO3− +NH(CH3)2(CH2)
n
CH3]2, where n = 7 or 11, respectively, and where Fc = ferrocene. Chemical structures were confirmed by microelemental analysis, FTIR, and
1H NMR spectroscopy. The critical micelle concentration of each prepared surfactant was determined using equilibrium surface
tension. Furthermore, air/water interface parameters including effectiveness (π
CMC), efficiency (Pc20), maximum surface excess (Гmax), and minimum surface area (A
min) were determined at 30, 40, and 50 °C. Thermodynamic parameters (ΔG°, ΔS°, and ΔH°) for both micellization and adsorption processes were recorded. The new synthesized surfactants were screened as antimicrobial
agents against different bacterial and fungal organisms. 相似文献
18.
A Si thin film of thickness 275 nm was deposited on rough Cu foil by magnetron sputtering for use as lithium ion battery anode
material. X-ray diffraction (XRD) and TEM analysis revealed that the Si thin film was completely of amorphous structure. The
electrochemical performance of the Si thin film was investigated by cyclic voltammetry and constant current charge/discharge
test. The film exhibited a high capacity of 3,134 mAh g−1 at 0.025 C rate. The capacity retention was 61.3% at 0.5 C rate for 500 cycles. An island structure formed on the Cu foil
substrate after cycling adhered to the substrate firmly and provided electrical connection. This is the possible reason for
the long cycling life of Si thin film anode. Moreover, the cycling performance was further improved by annealing at 300 °C.
The Li+ diffusion coefficients (D
0) of Si thin film, measured by cyclic voltammetry, are 1.47 × 10−9 cm2 s−1 and 2.16 × 10−9 cm2 s−1 for different reduced peaks. 相似文献
19.
ABSTRACTDuring the extraction of lithium from high Mg-containing salt lake brines by tributyl phosphate (TBP) in the presence of Fe(III), H+ is used to stabilize Fe(III). However, the distribution ratio of H+ (DH) is 4–6 times higher than that of Li+ (DLi), which affects the extraction of Li+ significantly. In this study, the competition mechanism between H+ and Li+ was investigated by spectral analysis and thermodynamic equilibrium. The extracted species are determined as HFeCl4 · 2TBP and LiFeCl4 · 2TBP for H+ and Li+, respectively. The apparent equilibrium constants are KH = 799.8 and KLi = 120.6, respectively. Both equilibrium constants and the distribution ratios for H+ and Li+ extraction show that extraction of H+ is stronger than Li+. 相似文献
20.
Yuanyuan Sun Shuhua Han Xiaojuan Yu Hongwei Che Aifeng Liu Shasha Wang 《Journal of Porous Materials》2010,17(5):597-603
Highly ordered supermicroporous silica was synthesized by short chains cationic trimeric surfactant [C10H21N+(CH3)2(CH2)2N+(CH3)(C10H21) (CH2)2N+(CH3)2C10H21] · 3Br− (denoted C10-2-10-2-10) with a short spacer group (s = 2) as the structure-directing agent and tetraethyl orthosilicate as the precursor. The obtained samples were characterized
by small-angle X-ray diffraction, high resolution transmission electron microscopy, and N2 adsorption–desorption. The results showed that the pore structure of the resulting samples belonged to the two-dimensional
hexagonal structure (space group 2D-p6mm) with a pore size from 1.92 to 2.16 nm, which was within the supermicroporous range. The high-quality supermicroporous silica
was formed at a low molar ratio of C10-2-10-2-10 to tetraethyl orthosilicate (0.08:1), which indicated that the self-assembly ability of C10-2-10-2-10 was stronger than that of corresponding monovalent surfactants. We strictly compared the methods of calculating surface area
and pore size of supermicroporous materials, and the surface area was found to be in the range of 910–1,135 m2 g−1 by the αs plot method. With the increase of hydrothermal temperature, the ordering of the supermicroporous structure increased first
then decreased, at the same time the pore size was enlarged. 相似文献