Kim Ju Hyeon, Lee Ju Hwan, Palem Ramasubba Reddy, Suh Min-Soo, Lee Hong H, Kang Tae June
Department of Mechanical Engineering, INHA University, Incheon, 22212, South Korea.
Energy Efficiency and Materials Research Division, Korea Institute of Energy Research, Daejeon, 34129, South Korea.
Sci Rep. 2019 Jun 18;9(1):8706. doi: 10.1038/s41598-019-45127-w.
Remarkable advances have recently been made in the thermocell array with series or parallel interconnection, however, the output power from the thermocell array is mainly limited by the electrolyte performance of an n-type element. In this work, we investigate iron (II/III) perchlorate electrolytes as a new n-type electrolyte and compared with the ferric/ferrous cyanide electrolyte at its introduction with platinum as the electrodes, which has been the benchmark for thermocells. In comparison, the perchlorate electrolyte (Fe/Fe) exhibits a high temperature coefficient of redox potential of +1.76 mV/K, which is complementary to the cyanide electrolyte (Fe(CN)/Fe(CN)) with the temperature coefficient of -1.42 mV/K. The power factor and figure of merit for the electrolyte are higher by 28% and 40%, respectively, than those for the cyanide electrolyte. In terms of device performance, the thermocell using the perchlorate electrolyte provides a power density of 687 mW/m that is 45% higher compared to the same device but with the cyanide electrolyte for a small temperature difference of 20 °C. The advent of this high performance n-type electrolyte could open up new ways to achieve substantial advances in p-n thermocells as in p-n thermoelectrics, which has steered the way to the possibility of practical use of thermoelectrics.
最近，串联或并联互连的热电池阵列取得了显著进展，然而，热电池阵列的输出功率主要受n型元件的电解质性能限制。在这项工作中，我们研究了高氯酸铁（II/III）电解质作为一种新型n型电解质，并将其与铁氰化铁/亚铁氰化铁电解质在引入铂作为电极时进行了比较，铁氰化铁/亚铁氰化铁电解质一直是热电池的基准。相比之下，高氯酸盐电解质（Fe/Fe）的氧化还原电位温度系数为+1.76 mV/K，与温度系数为-1.42 mV/K的氰化物电解质（Fe(CN)/Fe(CN)）互补。该电解质的功率因数和品质因数分别比氰化物电解质高28%和40%。在器件性能方面，使用高氯酸盐电解质的热电池在20°C的小温差下提供的功率密度为687 mW/m²，比使用氰化物电解质的相同器件高45%。这种高性能n型电解质的出现可能为实现p-n热电池的重大进展开辟新途径，就像p-n热电学一样，这为热电学的实际应用可能性指明了方向。
