Can charged colloidal particles increase the thermoelectric energy conversion efficiency?
Currently, liquid thermocells are receiving increasing attention as an inexpensive alternative to conventional solid-state thermoelectrics for low-grade waste heat recovery applications. Here we present a novel path to increase the Seebeck coefficient of liquid thermoelectric materials using charged colloidal suspensions; namely, ionically stabilized magnetic nanoparticles (ferrofluids) dispersed in aqueous potassium ferro-/ferri-cyanide electrolytes. The dependency of thermoelectric potential on experimental parameters such as nanoparticle concentration and types of solute ions (lithium citrate and tetrabutylammonium citrate) is examined to reveal the relative contributions from the thermogalvanic potential of redox couples and the entropy of transfer of nanoparticles and ions. The results show that under specific ionic conditions, the inclusion of magnetic nanoparticles can lead to an enhancement of the ferrofluid's initial Seebeck coefficient by 15% (at a nanoparticle volume fraction of ∼1%). Based on these observations, some practical directions are given on which ionic and colloidal parameters to adjust for improving the Seebeck coefficients of liquid thermoelectric materials.
Service de Physique de L'État Condensé, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France. sawako.nakamae@cea.fr and École des Ponts ParisTech, 6 et 8 avenue Blaise Pascal, Champs-sur-Marne, F-77455 Marne-la-Vallée, France.
Thomas J
http://orcid.org/0000-0003-2236-2726
TJ
Salez
Service de Physique de L'État Condensé, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France. sawako.nakamae@cea.fr.
Bo Tao
BT
Huang
Service de Physique de L'État Condensé, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France. sawako.nakamae@cea.fr.
Maud
M
Rietjens
Service de Physique de L'État Condensé, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France. sawako.nakamae@cea.fr.
Marco
M
Bonetti
Service de Physique de L'État Condensé, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France. sawako.nakamae@cea.fr.
Cécile
C
Wiertel-Gasquet
Service de Physique de L'État Condensé, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France. sawako.nakamae@cea.fr.
Michel
M
Roger
Laboratoire Physicochimie des Electrolytes et Nanosystèmes interfaciaux, UMR CNRS 8234, Université Pierre et Marie Curie - Paris 6, 4 place Jussieu, F-75009 Paris 5, France and Grupo de Fluidos Complexos - Instituto de Quimica, Universidade de Brasilia, CP 04478, 70904-970 Brasilia (DF), Brazil.
Cleber Lopes
CL
Filomeno
Laboratoire Physicochimie des Electrolytes et Nanosystèmes interfaciaux, UMR CNRS 8234, Université Pierre et Marie Curie - Paris 6, 4 place Jussieu, F-75009 Paris 5, France.
Emmanuelle
E
Dubois
Laboratoire Physicochimie des Electrolytes et Nanosystèmes interfaciaux, UMR CNRS 8234, Université Pierre et Marie Curie - Paris 6, 4 place Jussieu, F-75009 Paris 5, France.
Régine
R
Perzynski
Service de Physique de L'État Condensé, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France. sawako.nakamae@cea.fr.
Sawako
S
Nakamae