Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9760353 | Journal of Power Sources | 2005 | 5 Pages |
Abstract
The structure of two amphiphilic low-dimensional copolymer electrolytes I of similar overall composition but prepared by different synthetic procedures is described. I are copolymers of poly [2,5,8,11,14-pentaoxapentadecamethylene(5-alkyloxy-1,3-phenylene)] (CmO5) and poly[2,-oxatrimethylene(5-alkyloxy-1,3-phenylene)] (CmO1) where the alkyl side chains having m carbons are mixed dodecyl/octadecyl (50/50). 1H NMR shows that the copolymers have only 18 and 13% of CmO5 units in which LiBF4 ions are separated by Li+ encapsulation in tetraethoxy segments but molecular modelling suggests that in ionophobic CmO1 units the salt is mostly present as neutral aggregates decoupled from the polymer. Conductivities of microphase-separated mixtures with salt-bridge amphiphilic polyethers II and III of each system are similar. They have low temperature dependence over the range 20-110 °C at â¼10â3 S cmâ1. A conduction mechanism is proposed whereby Li+ hopping takes place along rows of decoupled aggregates in an essentially block copolymer structure. Subambient measurements to â10 °C gave a conductivity of 4 Ã 10â5 S cmâ1.
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Physical Sciences and Engineering
Chemistry
Electrochemistry
Authors
Y. Zheng, J. Liu, Y.-P. Liao, G. Ungar, P.V. Wright,