Issue 3, 2019

Hexakis(2,3,6-tri-O-methyl)-α-cyclodextrin–I5 complex in aqueous I/I3 thermocells and enhancement in the Seebeck coefficient

Abstract

A large Seebeck coefficient (Se) of 1.9 mV K−1 was recorded for the I/I3 thermocell by utilizing the host-guest complexation of hexakis(2,3,6-tri-O-methyl)-α-cyclodextrin (Me18-α-CD) with the oxidized iodide species. The thermocell measurement and UV-vis spectroscopy unveiled the formation of an Me18-α-CD–pentaiodide (I5) complex, which is in remarkable contrast to the triiodide complex α-CD–I3 previously reported. Although the precipitation of the α-CD–I3 complex in the presence of an electrolyte such as potassium chloride is a problem in thermocells, this issue was solved by using Me18-α-CD as a host compound. The absence of precipitation in the Me18-α-CD and I/I3 system containing potassium chloride not only improved the Se of the I/I3 thermocell, but also significantly enhanced the temporal stability of its power output. This is the first observation that I5 species is formed in aqueous solution in a thermocell. Furthermore, the solution equilibrium of the redox couples was controlled by tuning the chemical structure of the host compounds. Thus, the integration of host-guest chemistry with redox couples extends the application of thermocells.

Graphical abstract: Hexakis(2,3,6-tri-O-methyl)-α-cyclodextrin–I5− complex in aqueous I−/I3− thermocells and enhancement in the Seebeck coefficient

Supplementary files

Article information

Article type
Edge Article
Submitted
27 Aug 2018
Accepted
21 Oct 2018
First published
22 Oct 2018
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2019,10, 773-780

Hexakis(2,3,6-tri-O-methyl)-α-cyclodextrin–I5 complex in aqueous I/I3 thermocells and enhancement in the Seebeck coefficient

Y. Liang, T. Yamada, H. Zhou and N. Kimizuka, Chem. Sci., 2019, 10, 773 DOI: 10.1039/C8SC03821J

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements