Low-hysteresis manganese hexacyanoferrate (MnHCF) aqueous battery for low-grade thermal energy harvesting

Abstract

It is desirable to gather enormous low-grade waste heat energy using effective thermal energy-harvesting systems since most of the waste heats are at the temperature below 170 °C. A thermally regenerative electrochemical cycle (TREC) is a reliable approach for converting heat into electricity with a thermodynamic cycle. Most up-to-date approaches to increase the heat-to-electricity conversion efficiency have focused on improving a temperature coefficient of a full cell. Herein, we report a manganese hexacyanoferrate (MnHCF) as a TREC cathode material, which has the temperature coefficient of −0.72 mV K−1. Also, the heat-to-electricity conversion efficiency of MnHCF is 5.17% (at ηHX = 0%), greater than that reported for a TREC. The low-hysteresis TREC cathode material imparted by the largest interplanar distance guides the practical direction for studying the thermally regenerative electrochemical cycle.