High Thermopower of Agarose‐Based Ionic Thermoelectric Gel Through Micellization Effect Decoupling the Cation/Anion Thermodiffusion

Abstract

Ionic thermoelectric (i‐TE) gels can have a high thermopower, if the thermodiffusion of mobile cation/anion is decoupled, attracting increasing attentions. Herein, it is shown a high p‐type i‐TE thermopower of 41.8 mV K−1 in agarose‐based ionic thermoelectric gels of AG‐x Na:DBS (AG: agarose, Na:DBS: sodium dodecyl benzene sulfonate). The exclusively high thermopower is relative to the successfully decoupling the thermodiffusion of cation Na+ and anion DBS−. A unique porous structure is formed due to the micellization of the amphiphilic DBS− with the hydrophilic benzenesulfonic group attached to the hydrous agarose gel chains, while the hydrophobic alkyl chain point to the pore centers. As a result, the DBS− micelles are almost immobile as compared with Na+, which can be reconsidered as a part of the gel matrix. The work shines a light on decoupling of cation/anion thermodiffusion through tailoring the microstructure of the quasi‐solid i‐TE materials.

Mixed Ionic–Electronic Conducting Hydrogels with Carboxylated Carbon Nanotubes for High Performance Wearable Thermoelectric Harvesters

“…Overall, all of the MIEC hydrogels developed herein exhibit a remarkable thermoelectric performance, with maximum ionic ZT (ZT i ) values of approximately 2.65 for DN5C-P, as shown in Figure b and Table . Furthermore, the performances of DN5C-P are compared with those of other MIEC and ionic conducting TE materials in Table . ,,− Here, the as-prepared hydrogels exhibit mechanical properties superior to those of commonly used PEDOT:PSS-based TE materials for wearable devices. In particular, DN5C-P is seen to be highly competitive, exhibiting excellent ionic conductivity while maintaining a suitable Seebeck coefficient, thereby achieving an exceptional power factor.…”

Ultra-high performance of ionic thermoelectric-electrochemical gel cells for harvesting low grade heat

“…22–24 It shows a capacitive discharge characteristic due to the transferred non-Faraday current, which could reactivate after removing the temperature difference. 16 Gradually increased ionic thermopower from 10 to 24, 28, 35, and 42 mV K −1 was achieved for i-TE gels PEO–NaOH, 23 PEO–NaOH cellulose, 24 Gelatin–CF 3 SO 3 K–CH 3 SO 3 K, 25 WPU/EMIM:DCA 26 and AG- x Na:DBS, 27 respectively. In our previous work, a synergy of thermogalvanic and thermodiffusion effects in gels Gelatin–KCl–FeCN 4−/3− contributed to a high ionic thermopower of 17.0 mV K −1 and a maximum output power density of P max /(Δ T ) 2 = 0.66 mW m −2 K −2 .…”