Understanding Correlation Effects for Ion Conduction in Polymer Electrolytes

Maitra, Arijit; Heuer, Andreas

doi:10.1021/jp711563a

Cited by 28 publications

(38 citation statements)

References 28 publications

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“…The chain diffusion in this poly[bis(methoxyethoxy)phosphazene] salt in polymer (MEEP) system is an order of magnitude slower compared to lithium cations . In computer simulations, a coordination of the lithium by five oxygens has been determined …”

Section: Resultsmentioning

confidence: 99%

NMR study of photo‐crosslinked solid polymer electrolytes: The influence of monofunctional oligoethers

Chiappone

Jeremias

Bongiovanni

et al. 2013

J Polym Sci B Polym Phys

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Solid polymer electrolytes for Lithium batteries applications are commonly prepared by dissolving a lithium salt in poly(ethylene oxide) (PEO)‐based materials. Their performance is strongly related to the structure of the polymer network. In this article, a new salt‐in‐polymer electrolyte prepared by the fast and easy radical photopolymerization of PEO acrylate oligomers is studied. Here, a difunctional monomer used as the polymer backbone is copolymerized with monofunctional monomers of different length and concentration. Thus, the crosslinking density and conductivity are changed. These systems are investigated by a detailed NMR study yielding local dynamics and mass transport by temperature‐dependent spin‐lattice relaxation time and PFG‐NMR diffusion measurements for different nuclei (7Li and 19F). The results indicate that a sufficiently long monofunctional oligoether improves the properties, since it provides a lower crosslinking density as well as more coordinating oxygens for the Li ions. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1571–1580

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Section: Resultsmentioning

confidence: 99%

NMR study of photo‐crosslinked solid polymer electrolytes: The influence of monofunctional oligoethers

Chiappone

Jeremias

Bongiovanni

et al. 2013

J Polym Sci B Polym Phys

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“…8. It shows that even at O : Li ratios far above the number of EO groups coordinating a Li ion of 5-6 [61]. there is already a competition of Li ions for coordination sites and the activation energies become strongly dependent on salt concentration.…”

Section: Effect Of Oligoether Chain Lengthmentioning

confidence: 99%

“…The fact that the proton local dynamics is fast compared to that of Li can be rationalized as follows: if Li is coordinated to 5 oxygens in the side chains, which Maitra and Heuer [61] show by computer simulations, then the local Li dynamics depend on the statistics of binding and unbinding to all these oxygens. In contrast, for each single ethylene oxide group and the local dynamics of its protons, the binding and unbinding statistics of just one single O−Li coordinative bond is relevant.…”

Section: Local Ion Dynamicsmentioning

confidence: 99%

Transport Mechanisms of Ions in Graft-Copolymer Based Salt-in-Polymer Electrolytes

Kunze

Schulz

Wiemhöfer

et al. 2010

Zeitschrift Für Physikalische Chemie

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Polymer Electrolyte / Nuclear Magnetic Resonance / Spin Relaxation / Pulsed Field Gradient NMR / ConductivitySalt-in-polymer electrolytes based on graft copolymers with oligoether side chains and added LiCF 3 SO 3 (LiTf) are investigated concerning the transport and dynamics of the ionic species with respect to applications as Li ion conductors. Polymer architectures are based on polysiloxane or polyphosphazene backbones with one or two side chains per monomer, respectively. NMR methods provide information about molecular dynamics on different length scales: The mechanisms governing local dynamics and long range mass transport are studied on the basis of temperature dependent spin-lattice relaxation rates and pulsed field gradient diffusion measurements for 7 Li, 19 F and 1 H, respectively. The correlation times characterizing local ion dynamics reflect the complexation of the cations by the oligoether side chains of the polymer.7 Li and 19 F diffusion coefficients and their activation energies are rather similar, suggesting the formation of ion pairs and clusters with similar activation barriers for cation and/or anion long-range transport. Activation energies of local reorientations are generally significantly smaller than activation energies of long range diffusion. Long range transport is affected by (1) the coupling of conformational side chain reorientations to the cation movement, and (2) the correlated diffusion of cations and anions within ion pairs. Ion pairs and their dissociation play a major role in controlling the resulting conductivity of the material. Guidelines for material optimization in terms of a maximized conductivity can thus be derived by identifying a compromise between high ionic mobility and good Li complexation by the coordinating side chains.

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“…Recent MD simulations of ion transport in the PEO-LiI system have shown that the diffusivities of the cation and the corresponding cation-anion pair are closely similar, whereas the anion diffusivity appeared to be partly decoupled from the polymer-segment dynamics [25]. In the present formulation, this translates to D This specific variant of the general model will be preferentially used in the following sections for the evaluation of the experimental data.…”

Section: A Model To Combine Diffusion Data With Ionic Conductivity Mementioning

confidence: 91%

“…Since these assumptions are not unequivocal, this eventually leads to a distinction between two different submodels, one of which (Model #1) has been employed in previous work by our group [9,22]. The other submodel (Model #2), footing on the results of recent molecular dynamic (MD) calculations [25], is preferred in our newer publications [20,26]. For convenience, a list of symbols designating the physical quantities and parameters used in the models is presented in Table 1.…”

Section: A Model To Combine Diffusion Data With Ionic Conductivity Mementioning

confidence: 99%

The Use of Radiotracer Diffusion to Investigate Ionic Transport in Polymer Electrolytes: Examples, Effects, and Their Evaluation

Stolwijk¹,

Wiencierz

Fögeling

et al. 2010

Zeitschrift Für Physikalische Chemie

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The paper highlights some remarkable results obtained by applying the radiotracer diffusion (RTD) technique to the study of ionic transport in salt-in-polymer electrolytes. The technique is based on the determination of a radiotracer depth profile by serial sectioning following isothermal diffusion annealing. Unlike alternative methods, RTD is able to measure the self-cation and self-anion diffusivity even for systems dilute in salt. Another unique feature is the capability to investigate foreign-ion diffusion at extremely low concentration levels. Combined with DC conductivity data, RTD may provide a virtually complete picture of mass and charge transport in solid-like polymer electrolytes (SPEs). The paper describes the special SPE-related procedures used in the RTD experiments and their analysis. The advantages of the method will be demonstrated with selected examples of self-and foreign-ion diffusion in prototype SPE systems. We also present prominent examples of RTD dealing with the effects of salt precipitation and oxide nano-particles used as dispersed filler material.

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Understanding Correlation Effects for Ion Conduction in Polymer Electrolytes

Cited by 28 publications

References 28 publications

NMR study of photo‐crosslinked solid polymer electrolytes: The influence of monofunctional oligoethers

NMR study of photo‐crosslinked solid polymer electrolytes: The influence of monofunctional oligoethers

Transport Mechanisms of Ions in Graft-Copolymer Based Salt-in-Polymer Electrolytes

The Use of Radiotracer Diffusion to Investigate Ionic Transport in Polymer Electrolytes: Examples, Effects, and Their Evaluation

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