[Abstract]

Although ionic hydrogels have been developed recently for innovative wearable electronics, they necessitate high humidity to diffuse ions in water and fast self-healing, which negatively impacts their performance and stability in ambient conditions (e.g., dry environments). In this study, a series of p- and n-type polymeric ionic gels (PIGs) with different ratios of ionic side chains are synthesized to allow only single-type ions to pass through them. The results demonstrate that our repeatedly stretchable PIGs are transparent, thermally robust up to 125 °C, and self-healing. Among the series of PIGs, p- and n-type PIGs with 75% ion moieties (P75 and N75) exhibit the optimum ionic conductivity (σi) (4.1×10-4 and 2.7×10-4 S cm-1) and ionic Seebeck coefficients (Si) (5.84, and -4.18 mV K-1) under ambient conditions (25 °C and relative humidity (RH) of 30%), resulting in ZTi values of 1.87×10-3 and 1.18×10-3. Moreover, the σi and Si of PIGs were almost consistent under extremely low RH 10%. Accordingly, P(([EMIM+][SPA])0.75-r-MA0.25) (P75) and P(([APTA][TFSI-])0.75-r-MA0.25) (N75) are used to achieve stretchable ionic thermoelectrics (iTEs) with stable operability under ambient conditions (RH of 30%), satisfying all of the requirements. The iTEs with five pairs of p/n couples exhibit a thermovoltage of up to ~0.8 V.

DOI: 10.1002/adfm.202305499

LINK: https://onlinelibrary.wiley.com/doi/10.1002/adfm.202305499