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Enhanced thermal energy harvesting performance of a cobalt redox couple in ionic liquid-solvent mixtures

Version 2 2024-06-04, 11:50
Version 1 2016-01-29, 07:30
journal contribution
posted on 2024-06-04, 11:50 authored by MA Lazar, D Al-Masri, DR Macfarlane, Jenny PringleJenny Pringle
Thermoelectrochemical cells are increasingly promising devices for harvesting waste heat, offering an alternative to the traditional semiconductor-based design. Advancement of these devices relies on new redox couple/electrolyte systems and an understanding of the interplay between the different factors that dictate device performance. The Seebeck coefficient (Se) of the redox couple in the electrolyte gives the potential difference achievable for a given temperature gradient across the device. Prior work has shown that a cobalt bipyridyl redox couple in ionic liquids (ILs) displays high Seebeck coefficients, but the thermoelectrochemical cell performance was limited by mass transport. Here we present the Se and thermoelectrochemical power generation performance of the cobalt couple in novel mixed IL/molecular solvent electrolyte systems. The highest power density of 880 mW m-2, at a ΔT of 70 °C, was achieved with a 31 (v/v) MPN-[C2mim][B(CN)4] electrolyte combination. The significant power enhancement compared to the single solvent or IL systems results from a combination of superior ionic conductivity and higher diffusion coefficients, shown by electrochemical analysis of the different electrolytes. This is the highest power output achieved to-date for a thermoelectrochemical cell utilising a high boiling point redox electrolyte.

History

Journal

Physical chemistry chemical physics

Volume

18

Pagination

1404-1410

Location

[London, Eng]

ISSN

1463-9076

Language

eng

Publication classification

C Journal article, C1 Refereed article in a scholarly journal

Copyright notice

2016, the Owner Societies

Issue

3

Publisher

Royal Society of Chemistry