Interfacial Effect Boosts the Performance of All‐Polymer Ionic Thermoelectric Supercapacitors. Issue 31 (25th September 2022)

• Record Type: Journal Article
• Authors: Mardi, Saeed; Zhao, Dan; Tybrandt, Klas; Reale, Andrea; Crispin, Xavier
• Is Part Of: Advanced materials interfaces. Volume 9:Issue 31(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-25
• Subjects: effective thermopowers -- interfacial potentials -- ionic thermoelectric supercapacitors -- thermodiffusion; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.202201058
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: Ionic thermoelectric supercapacitors (ITESCs) have recently been developed for converting low‐grade waste heat into electricity. Until now, most reports of ITESCs have been focused on the development of electrolytes, which then have been combined with a specific electrode material. Here, it is demonstrated that the electrode is not only critical for electrical energy storage but also greatly affects the effective thermopower ( S eff ) of an ITESC. It is shown that the same ion gel can generate a positive thermopower in an ITESC when using gold nanowire (AuNW) electrodes, while generating a negative thermopower when using poly(3, 4‐ethylendioxythiophene):polystyrene sulfonate (PEDOT:PSS) electrodes. The achieved negative sign of the S eff could be attributed to the Donnan exclusive effect from the polyanions in the PEDOT:PSS electrodes. After examining the thermovoltage, capacitance and charge retention performance of the two ITESCs, it is concluded that PEDOT:PSS is superior to AuNWs as electrodes. Moreover, a new strategy of constructing an ionic thermopile of multiple p‐ and n‐type legs is achieved by series‐connecting these legs with same electrolyte but different electrodes. Using interfacial effect at ionic gels/PEDOT:PSS electrode interface, an enhanced thermoelectric effect in ITESCs is obtained, which constitutes one more step towards efficient, low‐cost, flexible, and printable ionic thermoelectric modules for energy harvesting. Abstract : This study investigates the role of the electrodes in the ionic thermoelectric supercapacitors, which not only determine the energy storage density, but also the generate thermovoltage. Using the poly(3, 4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as electrodes provides high capacitance and increases the overall thermovoltage. The latter is the result of cationic selectivity in PEDOT:PSS, which adds an additional interfacial voltage (∆Φ) to the ionic Seebeck potential.