New insights into structural and electrochemical properties of anisotropic polymer electrolytes

Livshits, Ester; Kovarsky, R.; Lavie, N.; Hayashi, Yûji; Golodnitsky, Diana

doi:10.1016/j.electacta.2005.02.047

Cited by 21 publications

(14 citation statements)

References 19 publications

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“…We suggest that the magnetic torques and forces (the latter due to the gradient that produces the orientation) are believed to arise primarily from the diamagnetic susceptibility of the polymer chains. 74 Although the energies associated with reorientation through torques and translation through forces are expected to be small compared to kT, it is plausible that cooperative effects between parallel polymer chains can be sufficient to produce the observed results. Additional forces can also be transmitted from alignment effects on the ferromagnetic filler particles in close contact with the chains.…”

Section: 91mentioning

confidence: 99%

“…Although the presence of these fillers complicated the interpretation of the orientation effects, the nanocomposites were included in this study because of the generally high level of interest in these materials, and because of our conjecture that magnetic effects on the particles themselves and the particle surface/polymer interfaces would also yield new interactions, facilitating orientation perpendicular to the casting plane. 73,74,95 It is evident that the size of the particles is critical. Larger particles in the polymer matrix will remain randomly oriented and contribute little to the conductivity through dipolar alignment.…”

Section: 91mentioning

confidence: 99%

“…11), support our suggestion. 74 The second filler which was intended to induce the orientational order in PEs is that of aromatic dipeptide nanotubes coated by ferrofluid. The peptide nanotubes are formed as individual entities in aqueous solution by the self-association of a simple aromatic dipeptide -diphenylalanine.…”

Section: 91mentioning

confidence: 99%

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Review—On Order and Disorder in Polymer Electrolytes

Golodnitsky

Strauss

Greenbaum

2015

J. Electrochem. Soc.

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206

135

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This contribution presents an overview of more than three-decades-long studies of the structure and mechanism of ion conduction in polyethylene-oxide-based solid polymer electrolytes. Conductivity in polymer electrolytes has long been viewed as confined to the amorphous phase above the glass-transition temperature (Tg). Above Tg, polymer chain motion creates a dynamic, disordered environment that was thought to play a critical role in facilitating ion transport. Difficulty of finding the amorphous polymer with sufficient ionic conductivity has raised the fundamental question of whether polymer electrolytes are intrinsically inferior to other electrolytes in terms of their charge-transport capability. Recently, enhanced ionic conductivity has been detected in ordered (longitudinally stretched and cast under gradient magnetic field) polymer electrolytes, in crystalline ion-polyether 1:6 complexes and polymer-in-salt electrolytes. These results have opened a new trend in the search for ion transport in solid polymer electrolytes. The very latest publications present new hybrid-and block-co-polymers, a new class of functional materials (polymerized ionic liquids), and new promising approaches aimed at the development of polymer-based superionic conductors with rigid nanochannel architectures that enable rapid ion transport decoupled from segmental relaxation. Solid Polymer Electrolytes-Structure and Mechanism of Ion TransportMuch research deals with high-ionic-conductive polymer electrolytes because of their current and potential applications as electrochromic and temperature-sensitive printed electronics devices, biomedical sensors, supercapacitors, solar cells and batteries. Polymer electrolytes offer pronounced advantages over conventional liquid electrolytes. These include: a versatile shape, mechanical strength and stable contact between the electrode and electrolyte interfaces. In addition, solid electrolytes are safer than liquid electrolytes as they do not have a leakage problem and because of their nontoxic, low-vaporpressure, and non-flammable properties. [1][2][3][4][5][6][7] Ion-polyether complexes (or polymer electrolytes) were first discovered by Fenton, Parker and Wright in 1973. 8 Since then, such complexes have been prepared with many different monatomic ions and indeed many different polymeric ligands. Armand in 1979 recognized that Li + -polyether complexes could be used as solid electrolytes in electrochemical devices. 9The classic polymer electrolyte comprises organic macromolecules (usually polyether polymer) that are complexed with inorganic salts. The polymer matrix must contain a Lewis base (e.g. ethylene-oxide unit, -OCH 2 CH 2 -) to solvate the lithium salt. The salt-solvent mixing entropy consists mainly of two components: translational and configurational. Contrary to the case of water, the mixing entropy for the formation of polymer electrolytes is small or even positive. The incorporation of salts into the polymer inevitably reduces the freedom of polymer-chain motion, thus causing ...

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Section: 91mentioning

confidence: 99%

Section: 91mentioning

confidence: 99%

See 1 more Smart Citation

Review—On Order and Disorder in Polymer Electrolytes

Golodnitsky

Strauss

Greenbaum

2015

J. Electrochem. Soc.

Self Cite

206

135

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“…Golodnitsky and co-workers 17 18 19 20 21 22 23 24 25 have studied the effect of stretching on the ion conductivity of hot-pressed PEO and found that stretching enhances the conductivity parallel to the stretching axis (in-plane) by a factor of 3–40 17 18 19 . The conductivity in the perpendicular direction (through-plane), however, has been observed to decrease and was attributed to the stiffening of the polymer chains, suppression in ion hopping between chains, and the alignment of PEO helices oriented in the force direction, leaving only a few helices oriented in the through-plane direction 17 .…”

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In Situ Study of Strain-Dependent Ion Conductivity of Stretchable Polyethylene Oxide Electrolyte

Kelly

Ghadi

Berg

et al. 2016

Sci Rep

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There is a strong need in developing stretchable batteries that can accommodate stretchable or irregularly shaped applications including medical implants, wearable devices and stretchable electronics. Stretchable solid polymer electrolytes are ideal candidates for creating fully stretchable lithium ion batteries mainly due to their mechanical and electrochemical stability, thin-film manufacturability and enhanced safety. However, the characteristics of ion conductivity of polymer electrolytes during tensile deformation are not well understood. Here, we investigate the effects of tensile strain on the ion conductivity of thin-film polyethylene oxide (PEO) through an in situ study. The results of this investigation demonstrate that both in-plane and through-plane ion conductivities of PEO undergo steady and linear growths with respect to the tensile strain. The coefficients of strain-dependent ion conductivity enhancement (CSDICE) for in-plane and through-plane conduction were found to be 28.5 and 27.2, respectively. Tensile stress-strain curves and polarization light microscopy (PLM) of the polymer electrolyte film reveal critical insights on the microstructural transformation of stretched PEO and the potential consequences on ionic conductivity.

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“…Nanostructured polymer membranes that exhibit anisotropic ion transport have attracted much attention recently because they can be exploited as scaffolds and templates for efficient fabrication of various nanoscopic structures/objects, , as well as in electrochemical systems, such as high performance lithium ion batteries − and fuel cells. − In principle, a physical approach was used for preparing anisotropic polymer membranes containing low-dimensional ion conductors. For example, one-dimensional (1D) conductivity has been demonstrated in a track-etched polycarbonate membrane with nanopores, which were infiltrated with lithium ion or proton conductive polymers. , From the viewpoints of practical application and mass production, a chemical approach based on self-organization seems to offer the promising potential for introduction of anisotropic nanostructures to ion conducting materials, as the following remarkable progress has been made so far. − A variety of materials, including ionic liquids, liquid crystalline (LC) materials, ,− block copolymers, ,− dendrimers, and supramolecules, have been synthesized for the purpose of preparing nanostructured ion conductors with geometries varying from columnar 12,22 and layered − , to gyroidal structures. , When using the chemical methods to prepare patterned membranes, it is essential to have uniform alignment and coaxial orientation of the phase-segregated nanostructures on the macroscopic scale to guarantee a large and reproducible anisotropy. In light of their potential application to electrochemistry, the conductive nanochannels should be aligned perpendicular to the electrode surface. , Especially, Kato and Ohno succeeded in demonstrating both high conductivity and its large anisotropy up to three orders of magnitude in well-designed LC ionic liquid materials .…”

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confidence: 99%