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7955013 
Journal Article 
Size-dependent ionic conductivity observed for ordered mesoporous alumina-LiI composite 
Maekawa, H; Tanaka, R; Sato, T; Fujimaki, Y; Yamamura, T 
2004 
1 
Solid State Ionics
ISSN: 0167-2738 
175 
1-4 
281-285 
English 
WOS:000225990500056 
Ordered mesoporous Al2O3 was synthesized by a solution sol-gel method using neutral copolymer surfactants as templates. The pore size was controlled over the range of 2.8-12.5 nm by using different surfactant copolymers under different synthetic conditions. By utilizing cyclohexane as a cosolvent, mesoporous Al2O3 having relatively monodispersed particle size was obtained. Composites composed of the synthesized mesoporous Al2O3 and the lithium ion conductor (LiI) was prepared by heating the composite in a sealed Pyrex tube at 773 K. Composition dependence of the dc conductivity was determined from a single arc in the observed impedance spectra. The maximum dc electrical conductivity, 2.6 × 10-4 S cm-4 at 298 K, was observed for 50 LiI middot; 50 Al2O3 composite with 4.2 nm averaged mesoporosity, which was considerably higher than the previously reported Lil-alumina composites. A systematic dependence of conductivity upon pore size was observed, in which the conductivity increased with decreasing the pore size. 2004 Elsevier B.V. All rights reserved. 
lithium ion conductor; mesoporous alumina; nano size effect; interfacial effect