Efficient Harvesting Waste Heat by Zn-Ion Battery Under Thermally Regenerative Electrochemical Cycles.

Sun, Xiaoling; Chen, Hongyi; Li, Yitong; Zeng, Dewen; Qiu, Pengfei; Zeng, Huarong; Ji, Xiaobo; Chen, Lidong et al. · Adv Mater · 2025

basic_science · Level V

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Abstract

Typical technologies that can convert waste heat into electricity include thermoelectrics, thermionic capacitors, thermo-cells, thermal charge cells, and thermally regenerative electrochemical cycles. They have small thermal-to-electrical conversion efficiency or poor stability, severely hindering the efficient recovery of waste heat. Herein, a thermally regenerative electrochemical Zn-ion battery to work under Carnot-like mode to efficiently harvest waste heat into electricity is successfully developed. Through introducing Layered Double Hydroxides to modify the battery's anode reaction, a record absolute high temperature coefficient of 2.944 mV K<sup>-1</sup> is achieved in NiHCF/Zn battery, leading to a high thermal-to-electrical conversion efficiency of 26.08% of the Carnot efficiency and an extraordinary energy efficiency of 104.11% when the battery is charged at 50 °C and discharged at 5 °C. This work demonstrates that thermally regenerative electrochemical batteries can effectively harvest waste heat to provide a powerful energy conversion technology.