Membrane-Free Battery for Harvesting Low-Grade Thermal Energy
Author(s)Yang, Yuan; Loomis III, Robert James; Ghasemi, Hadi; Lee, Seok Woo; Wang, Yi J.; Cui, Yi; Chen, Gang; ... Show more Show less
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Efficient and low-cost systems are desired to harvest the tremendous amount of energy stored in low-grade heat sources (<100 °C). An attractive approach is the thermally regenerative electrochemical cycle (TREC), which uses the dependence of electrode potential on temperature to construct a thermodynamic cycle for direct heat-to-electricity conversion. By varying the temperature, an electrochemical cell is charged at a lower voltage than discharged; thus, thermal energy is converted to electricity. Recently, a Prussian blue analog-based system with high efficiency has been demonstrated. However, the use of an ion-selective membrane in this system raises concerns about the overall cost, which is crucial for waste heat harvesting. Here, we report on a new membrane-free battery with a nickel hexacyanoferrate (NiHCF) cathode and a silver/silver chloride anode. The system has a temperature coefficient of −0.74 mV K[superscript –1]. When the battery is discharged at 15 °C and recharged at 55 °C, thermal-to-electricity conversion efficiencies of 2.6% and 3.5% are achieved with assumed heat recuperation of 50% and 70%, respctively. This work opens new opportunities for using membrane-free electrochemical systems to harvest waste heat.
DepartmentMassachusetts Institute of Technology. Department of Mechanical Engineering
American Chemical Society (ACS)
Yang, Yuan, James Loomis, Hadi Ghasemi, Seok Woo Lee, Yi Jenny Wang, Yi Cui, and Gang Chen. “Membrane-Free Battery for Harvesting Low-Grade Thermal Energy.” Nano Lett. 14, no. 11 (November 12, 2014): 6578–6583.
Author's final manuscript