Crystalline Polymer Electrolytes

Fig. 7.22 Detail of typical crystalline polymer electrolyte phase showing PEO helix surrounding liLhium ions...

The Arrhenius plot in which log oT is plotted against T 1 show straight lines. Generally it has been observed that this plot is followed by conventional solid electrolytes as well as crystalline polymer electrolytes. 

Gadjourova Z, Andreev Y, Tunstall D, Bruce P (2001) Ionic conductivity in crystalline polymer electrolytes. Nature 412 520-523... 

Christie AM, Lilley SJ, Staunton E et al (2005) Increasing the conductivity of crystalline polymer electrolytes. Nature 433 50-53... 

Cyclodexfrins have various configurations. When the a-form is added to a crystalline polymer electrolyte consisting of PEO and LiAsF, nanochannels are formed by the a-cyclodextrin, confining the PEO/Li+ complexes. The nanochannels provide pathways for the directional motion of LP ions and at the same time prevent the access of anions by size exclusion. As a result, the ionic conductivity of the electrolyte is 30 times higher than that of the comparable PEO/L1+ complex crystal at room temperature [24]. 

Figure 1.14 Temperature variation of the conductivity for selected crystalline polymer electrolytes. Unless stated otherwise, all complexes were prepared with 1000 Da PEO end-capped with -CH3. G4 is CH3-(CH2CH20)4-CH3...

Crystalline polymer electrolytes have been incorporated into lithium ion cells which are being shown to sustain cychng thus demonstrating potential for apphcations. " ... 

There is increasing interest in sodium-based batteries, because of the greater abundance and lower costs of sodium compared with lithium. Recently the first examples of crystalline polymer electrolytes that support Na" " conduction have been reported.Potassium and rubidium based crystalline polymer electrolytes have also been described. " This result is significant not only because these are the first Na, K" ", Rb, crystalline polymer electrolytes but also because they are the first example with a crystal structure that differs from the PEOg LiXF6 complexes. In the former case, the ratio of ether oxygens to cations is 8 1 rather than 6 1 and only one polymer chain wraps around the cations (Figure 1.15). 

GADJOUROVA z, ANDREEV Y G, TUNSTALL D p and BRUCE p G, lonlc Conductivity in crystalline polymer electrolytes . Nature, 2001, 412, 520-523... 

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