High-efficiency thermoelectrochemical conversion system based on H+-ion concentration cell stack

Abstract In fossil energy utilization processes, only about one-third of fuels is used effectively upon conversion, while the rest becomes waste heat. Therefore, making full use of waste heat is an effective way to save energy. Nowadays, the moderate-high temperature heat utilization systems continue to mature and develop. However, existing heat-to-electricity energy conversion technologies are not very efficient for utilization of low-grade waste heat. Herein, based on our previous finding in H+-ion concentration power generator, we design a cell stack structure in series to optimize and improve its thermal-to-electric performance with temperatures ranging from 50 °C to 170 °C. This experiment reveals that the thermal-to-electric conversion efficiency of 3-cell stack can reach up to 17.86%, which is more than twice as likely to a single-cell (8.39%). The electrochemical kinetic analysis and temperature distribution thermoanalysis results convince us that this tandem device is beneficial to the development for low-level heat recovery.