Role of Ions in Hydrogels with an Ionic Seebeck Coefficient of 52.9 mV K-1

Yongjie He; Qi Zhang; Hanlin Cheng; Yang Liu; Yue Shu; Yang Geng; Yujie Zheng; Bo Qin; Yongli Zhou; Shanshan Chen; Jing Li; Meng Li; George Omololu Odunmbaku; Chen Li; Tatyana Shumilova; Jianyong Ouyang; Kuan Sun

doi:10.1021/acs.jpclett.2c00845

Role of Ions in Hydrogels with an Ionic Seebeck Coefficient of 52.9 mV K^-1

J Phys Chem Lett. 2022 May 26;13(20):4621-4627. doi: 10.1021/acs.jpclett.2c00845. Epub 2022 May 19.

Authors

Yongjie He¹, Qi Zhang¹, Hanlin Cheng², Yang Liu¹, Yue Shu¹, Yang Geng¹, Yujie Zheng³, Bo Qin⁴, Yongli Zhou¹, Shanshan Chen³, Jing Li¹, Meng Li¹, George Omololu Odunmbaku¹, Chen Li¹, Tatyana Shumilova⁵, Jianyong Ouyang², Kuan Sun¹

Affiliations

¹ MOE Key Laboratory of Low-grade Energy Utilization Technologies and Systems, CQU-NUS Renewable Energy Materials & Devices Joint Laboratory, School of Energy & Power Engineering, Chongqing University, Chongqing 400044, China.
² Department of Materials Science and Engineering, National University of Singapore, Singapore 117574.
³ State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Energy & Power Engineering, Chongqing University, Chongqing 400044, China.
⁴ School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, China.
⁵ Institute of Geology, FRC Komi Science Center, Ural Branch, Russian Academy of Sciences, 167982 Syktyvkar, Russia.

PMID: 35587455
DOI: 10.1021/acs.jpclett.2c00845

Abstract

Ionic thermoelectric (i-TE) material with mobile ions as charge carriers has the potential to generate large thermal voltages at low operating temperatures. This study highlights the role of ions in i-TE hydrogels employing a poly(vinyl alcohol) (PVA) polymer matrix and a number of ion providers, e.g., KOH, KNO₃, KCl, KBr, NaI, KI, and CsI. The relationship between the intrinsic physical parameters of the ion and the thermoelectric performance is established, indicating the ability to influence the hydrogen bond by the ion is a crucial factor. Among these i-TE hydrogels, the PVA/CsI hydrogel exhibits the largest ionic Seebeck coefficient, reaching 52.9 mV K^-1, which is the largest of all i-TE materials reported to date. In addition, our work demonstrates the influence of ions on polymer configuration and provides an avenue for ion selection in the Soret effect in ionic thermoelectrics.