Hierarchically Anisotropic Networks to Decouple Mechanical and Ionic Properties for High-Performance Quasi-Solid Thermocells

Wei Gao; Zhouyue Lei; Wenwen Chen; Yongping Chen

doi:10.1021/acsnano.2c02606

Hierarchically Anisotropic Networks to Decouple Mechanical and Ionic Properties for High-Performance Quasi-Solid Thermocells

ACS Nano. 2022 May 24;16(5):8347-8357. doi: 10.1021/acsnano.2c02606. Epub 2022 Apr 22.

Authors

Wei Gao^{1

2

3}, Zhouyue Lei², Wenwen Chen⁴, Yongping Chen^{1

3}

Affiliations

¹ Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, P. R. China.
² John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge 02138, Massachusetts, United States.
³ Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, P. R. China.
⁴ Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, School of Biomedical Engineering, Shenzhen University Health Science Center, Shenzhen 518060, P. R. China.

PMID: 35452232
DOI: 10.1021/acsnano.2c02606

Abstract

The rapid growth of wearable systems demands sustainable, mechanically adaptable, and eco-friendly energy-harvesting devices. Quasi-solid ionic thermocells have demonstrated the capability of continuously converting low-grade heat into electricity to power wearable electronics. However, a trade-off between ion conductivity and mechanical properties is one of the most challenging obstacles for developing high-performance quasi-solid thermocells. Herein, the trade-off is overcome by designing anisotropic polymer networks to produce aligned channels for ion-conducting and hierarchically assembled crystalline nanofibrils for crack blunting. The ionic conductivity of the anisotropic thermocell has a more than 400% increase, and the power density is comparable to the record of state-of-the-art quasi-solid thermocells. Moreover, compared with the existing quasi-solid thermocells with the optimal mechanical performance, this material realizes biomimetic strain-stiffening and shows more than 1100% and 300% increases in toughness and strength, respectively. We believe this work provides a general method for developing high-performance, cost-effective, and durable thermocells and also expands the applicability of thermocells in wearable systems.

Keywords: eco-friendly energy-harvesting materials; hierarchically anisotropic networks; ionic conductivity; mechanical toughness; quasi-solid thermocells.