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, we successfully developed a thermally regenerative Zn-ion battery to work under Carnot-like mode to efficiently harvest waste heat into electricity. Through introducing Layered Double Hydroxides to modify battery’s anode reaction, a record absolute high temperature coefficient of 2.944 mV/K is achieved in NiHCF/Zn battery, leading to a high thermal-to-electrical conversion efficiency of 29.24% of the Carnot efficiency and an extraordinary energy efficiency of 104.11% when the battery is charged at 50 ℃ and discharged at 5 ℃. This work demonstrates that the thermally regenerative batteries can effectively harvest waste heat to provide a powerful energy conversion technology.