Performance of a non-aqueous nanofluid thermally regenerative flow battery for electrical energy recovery from low-grade waste heat

Abstract

Non-aqueous thermally regenerative battery (non-aqueous TRB) operating at voltages above 1 V is a promising technology for converting low-grade waste heat into electrical energy. To improve the power generation of non-aqueous TRB, the operating parameters that affect the performance of non-aqueous TRB, including the membrane type, electrode materials, acetonitrile volume fraction and electrolyte flow rate were investigated through experimental research. In addition, the thermal-to-electric efficiency of non-aqueous TRB system with different acetonitrile volume fraction and active species concentration was investigated by theoretical calculation. Because of the enhanced active species transport, the optimized maximum power density value of 235 W m−2 was achieved with the use of an anion exchange membrane, reticulated vitreous carbon as the anode electrode, etched carbon felt as the cathode electrode, acetonitrile fraction of 70 %, and electrolyte flow rate of 35 mL min−1. Moreover, theoretical thermal efficiency of 6.6 % was calculated with consisting of 10 % acetonitrile and 0.5 M active species. The above optimized performance in this study is competitive and promotes the development and application of TRBs.