Ionically conducting polyether composites

1996 ◽  
Vol 74 (11) ◽  
pp. 2106-2113 ◽  
Author(s):  
J.R. Stevens ◽  
W. Wieczorek
Keyword(s):  
Ionic Conductivity ◽  
Lewis Acids ◽  
Room Temperature ◽  
Lewis Base ◽  
Filler Concentration ◽  
Composite Electrolyte ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Conductivity Enhancement ◽  
Ambient Temperatures

Ionic conductivity in polymer–salt electrolytes occurs in the amorphous regions of the complex. Poly(ethylene oxide) (PEO) is the best polyether for complexing salts. Unfortunately, it is partially crystalline at ambient temperatures. With inorganic (i.e., alumina) or organic (i.e., poly(acrylamide) (PAAM)) fillers the crystallization of PEO is inhibited and the room temperature conductivity is enhanced in these mixed phase systems by over two orders of magnitude (to ~ 10−4 S/cm) above the base PEO–salt system (<10− S/cm). Even adding PAAM to an initially amorphous system (oxymethylene-linked PEO–LiClO4) increases the room temperature conductivity by 2 to 3 times. Various alkali metal salts (Li, Na) and NH4SCN are used with α-Al2O3, θ-Al2O3, PAAM′ and poly(N,N′-dimethyl acrylamide) as fillers. The aluminas stiffen the complex and increase Tg. The addition of the organic fillers lowers Tg, as is to be preferred. It is suggested that changes in the conductivity with changes in salt and filler concentration are due to changes in the ultrastructure and morphology and are the result of an equilibrium between various Lewis acid – Lewis base reactions. Qualified success has been achieved in modelling ionic conductivity in these composite electrolyte systems using an effective medium approach. In this approach it has been assumed that the main conductivity enhancement takes place in thin amorphous layers of the polyether that coat the dispersed polyacrylamide particles separated in a microphase. In the best complexes this layer is identified by a second Tg. Key words: polyethers, composites, ionic conductivity, phase structure, Lewis acids and bases.

A comparative study of Li10.35Ge1.35P1.65S12 and Li10.5Ge1.5P1.5S12 superionic conductors

2020 ◽  
Vol 13 (06) ◽  
pp. 2050031
Author(s):  
Yue Jiang ◽  
Zhiwei Hu ◽  
Ming’en Ling ◽  
Xiaohong Zhu
Keyword(s):  
Ionic Conductivity ◽  
Room Temperature ◽  
Ionic Conductivities ◽  
Lithium Ion ◽  
Lattice Parameter ◽  
Superionic Conductors ◽  
Chemical Compositions ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Ion Conductor

Since the lithium-ion conductor Li[Formula: see text]GeP2S[Formula: see text] (LGPS) with a super high room-temperature conductivity of 12[Formula: see text]mS/cm was first reported in 2011, sulfide-type solid electrolytes have been paid much attention. It was suggested by Kwon et al. [J. Mater. Chem. A 3, 438 (2015)] that some excess lithium ions in LGPS, namely, Li[Formula: see text]Ge[Formula: see text] P[Formula: see text]S[Formula: see text], could further improve their ionic conductivities, and the highest conductivity of 14.2[Formula: see text]mS/cm was obtained at [Formula: see text] though a larger lattice parameter that occurred at [Formula: see text]. In this study, we focus on these two different chemical compositions of LGPS with [Formula: see text] and [Formula: see text], respectively. Both samples were prepared using the same experimental process. Their lattice parameter, microstructure and room-temperature ionic conductivity were compared in detail. The results show that the main phase is the tetragonal LGPS phase but with a nearly identical amount of orthorhombic LGPS phase coexisting in both samples. Bigger lattice parameters, larger grain sizes and higher ionic conductivities are simultaneously achieved in Li[Formula: see text]Ge[Formula: see text]P[Formula: see text]S[Formula: see text] ([Formula: see text]), exhibiting an ultrahigh room-temperature ionic conductivity of 18.8[Formula: see text]mS/cm.

scholarly journals Controlled ionic conductivity via tapered block polymer electrolytes

RSC Advances ◽  
2015 ◽  
Vol 5 (17) ◽  
pp. 12597-12604 ◽  
Author(s):  
Wei-Fan Kuan ◽  
Roddel Remy ◽  
Michael E. Mackay ◽  
Thomas H. Epps, III
Keyword(s):  
Ionic Conductivity ◽  
Ethylene Oxide ◽  
Polymer Electrolytes ◽  
Room Temperature ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Block Polymer

Tapered block polymer electrolytes have been developed and exhibited enhanced room temperature conductivity relative to poly(styrene-b-ethylene oxide) (P(S-EO)) and non-tapered poly(s-b-oligo-oxyethylene methacrylate) (P(S-OEM)) counterparts.

Conductivity and Transport Properties Study of Plasticized Carboxymethyl Cellulose (CMC) Based Solid Biopolymer Electrolytes (SBE)

2013 ◽  
Vol 856 ◽  
pp. 118-122 ◽  
Author(s):  
A.S. Samsudin ◽  
M.I.N. Isa
Keyword(s):  
Ionic Conductivity ◽  
Carboxymethyl Cellulose ◽  
Room Temperature ◽  
Ethylene Carbonate ◽  
Casting Method ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Biopolymer Electrolytes ◽  
Arrhenius Relation ◽  
Solution Casting Method

Solid biopolymer electrolytes (SBE) comprising carboxymethyl cellulose (CMC) with NH4Br-EC were prepared by solution casting method. The samples were characterized by impedance spectroscopy (EIS) and sample containing 25wt. % of NH4Br exhibited the highest room temperature conductivity of 1.12 x 10-4S/cm for salted CMC based SBE system. The ionic conductivity increased to 3.31 x 10-3S/cm when 8 wt. % of ethylene carbonate (EC) was added to the highest conductivity. The conductivity-temperature of plasticized SBE system obeys the Arrhenius relation where the ionic conductivity increases with temperature. The influence of EC addition on unplasticized CMC based SBE was found to be dependent on the number and the mobility of the ions. This results revealed that the influence of plasticizer (EC) which was confirmed play the significant role in enhancement of ionic conductivity for SBE system.

scholarly journals Old Donors for New Molecular Conductors: Combining TMTSF and BEDT-TTF with Anionic (TaF6)1−x/(PF6)x Alloys

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 386
Author(s):  
Magali Allain ◽  
Cécile Mézière ◽  
Pascale Auban-Senzier ◽  
Narcis Avarvari
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Density Wave ◽  
Spin Density Wave ◽  
Orthorhombic Phase ◽  
Molecular Conductors ◽  
Bechgaard Salts ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Resistivity Measurements

Tetramethyl-tetraselenafulvalene (TMTSF) and bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF) are flagship precursors in the field of molecular (super)conductors. The electrocrystallization of these donors in the presence of (n-Bu4N)TaF6 or mixtures of (n-Bu4N)TaF6 and (n-Bu4N)PF6 provided Bechgaard salts formulated as (TMTSF)2(TaF6)0.84(PF6)0.16, (TMTSF)2(TaF6)0.56(PF6)0.44, (TMTSF)2(TaF6)0.44(PF6)0.56 and (TMTSF)2(TaF6)0.12(PF6)0.88, together with the monoclinic and orthorhombic phases δm-(BEDT-TTF)2(TaF6)0.94(PF6)0.06 and δo-(BEDT-TTF)2(TaF6)0.43(PF6)0.57, respectively. The use of BEDT-TTF and a mixture of (n-Bu4N)TaF6/TaF5 afforded the 1:1 phase (BEDT-TTF)2(TaF6)2·CH2Cl2. The precise Ta/P ratio in the alloys has been determined by an accurate single crystal X-ray data analysis and was corroborated with solution 19F NMR measurements. In the previously unknown crystalline phase (BEDT-TTF)2(TaF6)2·CH2Cl2 the donors organize in dimers interacting laterally yet no organic-inorganic segregation is observed. Single crystal resistivity measurements on the TMTSF based materials show typical behavior of the Bechgaard phases with room temperature conductivity σ ≈ 100 S/cm and localization below 12 K indicative of a spin density wave transition. The orthorhombic phase δo-(BEDT-TTF)2(TaF6)0.43(PF6)0.57 is semiconducting with the room temperature conductivity estimated to be σ ≈ 0.16–0.5 S/cm while the compound (BEDT-TTF)2(TaF6)2·CH2Cl2 is also a semiconductor, yet with a much lower room temperature conductivity value of 0.001 to 0.0025 S/cm, in agreement with the +1 oxidation state and strong dimerization of the donors.

scholarly journals Synthesis and Characterization of Lithium-Ion Conductive LATP-LaPO4 Composites Using La2O3 Nano-Powder

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3502
Author(s):  
Fangzhou Song ◽  
Masayoshi Uematsu ◽  
Takeshi Yabutsuka ◽  
Takeshi Yao ◽  
Shigeomi Takai
Keyword(s):  
Room Temperature ◽  
Conduction Mechanism ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
X Ray ◽  
Nano Powder ◽  
Powder Addition

LATP-based composite electrolytes were prepared by sintering the mixtures of LATP precursor and La2O3 nano-powder. Powder X-ray diffraction and scanning electron microscopy suggest that La2O3 can react with LATP during sintering to form fine LaPO4 particles that are dispersed in the LATP matrix. The room temperature conductivity initially increases with La2O3 nano-powder addition showing the maximum of 0.69 mS∙cm−1 at 6 wt.%, above which, conductivity decreases with the introduction of La2O3. The activation energy of conductivity is not largely varied with the La2O3 content, suggesting that the conduction mechanism is essentially preserved despite LaPO4 dispersion. In comparison with the previously reported LATP-LLTO system, although some unidentified impurity slightly reduces the conductivity maximum, the fine dispersion of LaPO4 particles can be achieved in the LATP–La2O3 system.

Structure and Conductivity of Iodine-Doped C60 Thin Films

1994 ◽  
Vol 359 ◽  
Author(s):  
Jun Chen ◽  
Haiyan Zhang ◽  
Baoqiong Chen ◽  
Shaoqi Peng ◽  
Ning Ke ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Room Temperature ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
X Ray ◽  
Thermally Activated ◽  
Order Of Magnitude

ABSTRACTWe report here the results of our study on the properties of iodine-doped C60 thin films by IR and optical absorption, X-ray diffraction, and electrical conductivity measurements. The results show that there is no apparent structural change in the iodine-doped samples at room temperature in comparison with that of the undoped films. However, in the electrical conductivity measurements, an increase of more that one order of magnitude in the room temperature conductivity has been observed in the iodine-doped samples. In addition, while the conductivity of the undoped films shows thermally activated temperature dependence, the conductivity of the iodine-doped films was found to be constant over a fairly wide temperature range (from 20°C to 70°C) exhibiting a metallic feature.

Ion transport studies in PVA:NH4CH3COO gel polymer electrolytes

2020 ◽  
Vol 32 (2) ◽  
pp. 208-219
Author(s):  
CP Singh ◽  
PK Shukla ◽  
SL Agrawal
Keyword(s):  
Ionic Conductivity ◽  
Ion Transport ◽  
Salt Concentration ◽  
Polymer Electrolytes ◽  
Poly Vinyl Alcohol ◽  
Infrared Analysis ◽  
Gel Polymer Electrolytes ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Mobility Of Charge Carriers

Ion conducting gel polymer electrolytes (GPEs) are being intensively studied for their potential applications in various electrochemical devices. The poly(vinyl alcohol)-based GPE films containing ammonium acetate (NH4CH3COO) salt have been studied for various concentrations of salt. The gel electrolyte films (GPEs) have been prepared using solution casting technique. Structural characterization carried out using X-ray diffraction reveals an increase in the amorphous nature of the samples on increasing salt concentration up to 70 wt%. The complexation of polymer and salt has been studied by Fourier-transform infrared analysis. Ionic conductivity of the GPEs has been found to increase with salt concentration and reaches an optimum for an intermediate concentration. The room temperature conductivity isotherm exhibits a maximum in conductivity of 2.64 × 10−4 Scm−1 for 65 wt% salt concentration. The temperature dependence of ionic conductivity exhibits a combination of Arrhenius and Vogel–Tamman–Fulcher behavior. Ion transport in the electrolyte system has been explored using dielectric response of the material and the observed variation in conductivity is suitably correlated to the change in charge carrier concentration and mobility of charge carriers.

Intercalation of Acceptors and Donors in Highly Ordered Graphite Fibers

1982 ◽  
Vol 20 ◽  
Author(s):  
T.C. Chieu ◽  
G. Timp ◽  
M.S. Dresselhaus
Keyword(s):  
Raman Spectroscopy ◽  
Room Temperature ◽  
Skin Depth ◽  
X Ray Diffraction ◽  
Repeat Distance ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
X Ray ◽  
Order Of Magnitude ◽  
Graphite Fibers

ABSTRACTThe intercalation of various acceptors and donors into graphite fibers, prepared from benzene-derived precursor materials is investigated by Raman spectroscopy, x-ray diffraction, electron diffraction, lattice fringing, and electrical resistivity measurements. Evidence for formation of well-staged acceptor compounds is provided by Debye-Scherrer x-ray diffraction which probes the bulk fiber and by Raman spectroscopy which probes an optical skin depth (< 0.1 μm). Lattice fringing measurements provide direct observation of large regions (up to 50 Aring; × 400 Aring;) of defectfree single-staged regions. Values for the c-axis repeat distance Ic are obtained by indexing (00l) lines of the x-ray diffraction pattern. Raman results show characteristic upshifted modes for stage 1 acceptor compounds with a sharpening in linewidth as compared to the E2g2 mode of the pristine fiber. The room temperature electrical conductivity is increased about an order of magnitude upon intercalation and exhibits a metallic dependence on temperature. The highest air-stable room temperature conductivity 1.4 × 105 (Ω-cm)−l ever reported for an intercalated fiber has been achieved.

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