TY - JOUR
T1 - Hybrid thermoelectrochemical and concentration cells for harvesting low-grade waste heat
AU - Kim, Kyunggu
AU - Kang, Junsik
AU - Lee, Hochun
N1 - Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/12/15
Y1 - 2021/12/15
N2 - Thermoelectrochemical cells (TECs) are promising platforms for thermal energy conversion. However, their widespread use is limited because of their low Seebeck coefficient and low conversion efficiency. We demonstrate a hybrid thermoelectrochemical and concentration cell based on carbonate solvents with a I3−/I− redox couple (referred to as i-TCC), which outperforms the current best n-type TEC employing an aqueous Fe3+/2+ redox couple. As the temperature of the hot side of i-TCC increases above 40 °C, dimethyl carbonate solvent reacts with iodide anions to form a porous Li2CO3-matrix near the hot electrode, which sustains long-lasting iodide-concentration gradient across the cell. The thermally driven concentration difference boosts the performance of the TEC to yield a remarkably high Seebeck coefficient (+7.7 mV K−1), figure of merit (ZT = 0.114), and Carnot efficiency (5.2%) for a temperature difference of 35 °C (25 °C and 60 °C for cold and hot temperatures, respectively). i-TCC demonstrated here thus provides a new perspective in harvesting low-grade waste heat.
AB - Thermoelectrochemical cells (TECs) are promising platforms for thermal energy conversion. However, their widespread use is limited because of their low Seebeck coefficient and low conversion efficiency. We demonstrate a hybrid thermoelectrochemical and concentration cell based on carbonate solvents with a I3−/I− redox couple (referred to as i-TCC), which outperforms the current best n-type TEC employing an aqueous Fe3+/2+ redox couple. As the temperature of the hot side of i-TCC increases above 40 °C, dimethyl carbonate solvent reacts with iodide anions to form a porous Li2CO3-matrix near the hot electrode, which sustains long-lasting iodide-concentration gradient across the cell. The thermally driven concentration difference boosts the performance of the TEC to yield a remarkably high Seebeck coefficient (+7.7 mV K−1), figure of merit (ZT = 0.114), and Carnot efficiency (5.2%) for a temperature difference of 35 °C (25 °C and 60 °C for cold and hot temperatures, respectively). i-TCC demonstrated here thus provides a new perspective in harvesting low-grade waste heat.
KW - Electrochemistry
KW - Energy conversion
KW - Energy harvesting
KW - Nucleophilic substitution
KW - Thermoelectrochemical cell
UR - http://www.scopus.com/inward/record.url?scp=85113679430&partnerID=8YFLogxK
U2 - 10.1016/j.cej.2021.131797
DO - 10.1016/j.cej.2021.131797
M3 - Article
AN - SCOPUS:85113679430
SN - 1385-8947
VL - 426
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
M1 - 131797
ER -