Phase Diagrams for the PEO-LiX Electrolyte System.

Munshi, M. Z. A.; Owens, Boone B.

doi:10.21236/ada176303

Cited by 3 publications

(3 citation statements)

References 10 publications

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“…It has been demonstrated that the effect of moisture on conductivity is largely reversible once the water is removed with heat. 25 It is logical that the effects of any other plasticizing solvents are also largely reversible. Based on this assumption, THF was chosen as the solvent for salt loading because it is easy to remove on heating.…”

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confidence: 99%

Tunable Networks from Thiolene Chemistry for Lithium Ion Conduction

et al. 2012

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End-functionalized poly(ethylene glycol) (PEG) and polydimethylsiloxane (PDMS) were cross-linked by a thiolene reaction with a tetra-functional thiol to create robust, tunable networks. These networks were loaded with increasing amounts of lithium bis(trifluoromethane sulfonyl imide) (LiTFSI), and their ion conductivity was measured. A wide range of salt loading was achieved, allowing the investigation of both salt-in-polymer and polymer-in-salt regimes. Thermal, mechanical, and ion conductivity properties of LiTFSI-loaded PEG and PEG-PDMS networks were measured. Even at high salt loadings, both networks maintained rubber-like characteristics, which were stable over a range of temperatures (30−90°C). The PEG network with the highest salt loading showed the greatest ion conductivity, 6.7 × 10 −4 S cm −1 at 30°C, as measured by impedance spectroscopy. This system provides a route to optimize lithium ion conduction and mechanical properties.A ccess to affordable, clean energy is a well-recognized scientific and technical challenge of this century.

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confidence: 99%

Tunable Networks from Thiolene Chemistry for Lithium Ion Conduction

et al. 2012

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“…This is because the molecular movements of the amorphous chains are reduced in highly crystalline polymers such as PEO resulting in a decrease in configurational entropy. 12 X-Ray studies 25 have shown that the material is highly crystalline, especially at the higher salt concentration. The results 25 also confirm the absence of free salt in all the films examined except the PEOLiA1Cl4 system.…”

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confidence: 99%

“…12 X-Ray studies 25 have shown that the material is highly crystalline, especially at the higher salt concentration. The results 25 also confirm the absence of free salt in all the films examined except the PEOLiA1Cl4 system. Previous studies 22 on this system also suggested the possibility of LiA1Cl 4 partially dissociating to LiCl and A1Cl 3 , although the extent of dissociation was unknown.…”

Section: Resultsmentioning

confidence: 99%

Ionic Transport in Poly(ethylene oxide) (PEO)-LiX Polymeric Solid Electrolyte

Munshi

Owens

1988

Polym J

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ABSTRACT:The ionic conductivity behavior of poly(ethylene oxide) complexed with lithium salts was investigated using an a.c. impedance technique. The composition range of the salt was from 0.01 to 0.5 mole fraction. The result showed that anions strongly influence the conductivity behavior of the polymer electrolyte. A simple model is proposed whereby the conductivity decrease at higher salt concentration is due to ion-pair formation. This results in an increase in the activation energy with increasing salt concentration and a reduction in the ionic mobility of Li+ ions. KEY WORDSPolymer Electrolytes/ Poly(ethylene oxide)/ Conductivity/ Ionic Transport / Ion-Pair / Fast ion transport was first demonstrated by Fenton et al.,1 on polymer solid electrolytes based on poly(ethylene oxide) (PEO) and an alkali metal salt at about I00°C. This was followed by Armand's proposal 2 for an allsolid state lithium battery. Since then there has been considerable interest in developing electrolytes based on these and other types of polymeric materials 3 -20 for use in high energy denisty batteries. PEO is by far the most widely studied polymer electrolyte. The pure polymer is highly crystalline ( > 60%) with a glass transition temperature of 213°K. The complex formed between PEO and an alkali metal salt imparts a high ionic conductivity in the elastomeric phase at tempertures above the melting point of PEO. However, the mechanism of ionic transport is not well understood. This is mainly due to a difference in opinion concerning the structure of the complex. The general occurrence of the complex at a stoichiometry of 4: 1 PEO: Li salt (termed O: Li ratio) led to the proposal of a helical strucute of the PEO strands with the lithium ions placed at the core of the helix 2 .However, this has recently been shown 21 to be in disagreement with experimental findings. The stoichiometry of the complex has been found to vary and O: Li ratios as low as 2.5: 1 have been found to exist. 22 X-ray analyses have shown the Li+ ions occupy positions outside the helical PEO strands. This would explain tbe observed stoichiometries lower than 4: 1, 0: Li. This conformation would result in a minimum coulombic repulsion 23 from the oxygen lone pairs.Phase diagrams of the PEO-LiX systems have shown that the complex formed is not single-phase but exists in two or more phases. At room temperature, three phases coexist; the pure PEO crystals, the salt rich stoichiometric crystalline complex and the amorphous phase. As the temperature is raised above 65°C, the crystalline PEO melts in the amorphous phase. It is at these elevated temperatures that the conductivity of the electrolyte becomes significant.Numerous studies have been made to eluci-577

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Ceramic polymer electrolytes

Syzdek

2010

Polymer Electrolytes

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Phase Diagrams for the PEO-LiX Electrolyte System.

Cited by 3 publications

References 10 publications

Tunable Networks from Thiolene Chemistry for Lithium Ion Conduction

Tunable Networks from Thiolene Chemistry for Lithium Ion Conduction

Ionic Transport in Poly(ethylene oxide) (PEO)-LiX Polymeric Solid Electrolyte

Ceramic polymer electrolytes

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