Engineering of solvation entropy by poly(4-styrenesulfonic acid) additive in an aqueous electrochemical system for enhanced low-grade heat harvesting

• Main Authors: Li, Jia, Li, Xiaoya, Lee, Donghoon, Yun, Jeonghun, Wu, Angyin, Jiang, Cheng, Lee, Seok Woo
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2023
• Subjects: Engineering::Electrical and electronic engineering; Low-Grade Heat Harveting; Thermally Regenerative Electrochemical Cycle
• Online Access: https://hdl.handle.net/10356/171429
• Institution: Nanyang Technological University

The thermally regenerative electrochemical cycle (TREC) is a reliable and efficient approach to converting low-grade heat into electricity. A high temperature coefficient (α) is the key to maximize the energy conversion efficiency of the TREC system. In this study, we present significant improvement of α of a Prussian blue analogue (PBA)-based electrochemical cell by adding poly(4-styrenesulfonic acid) (PSS) to the electrolyte. Raman spectra showed that water-soluble charged polymers strongly affect the ion hydration structure and increase the entropy change (ΔS) during ion intercalation in PBA. A large α of -2.01 mV K-1 and high absolute heat-to-electricity conversion efficiency up to 1.83% was achieved with a TREC cell in the temperature range 10-40 °C. This study provides a fundamental understanding of the origin of α and a facile method to boosting the temperature coefficient for building a highly efficient low-grade heat harvesting system.