Harvesting energy from low-temperature heat sources (<100°C) would enable the exploitation of currently untapped renewable sources. Recently proposed techniques fail to reach suitable efficiencies. We propose here a redox flow battery that can be recharged by a thermal process, distillation. The electrochemical cell produces electrical energy from the mixing free energy of two sodium iodide aqueous solutions at different concentrations. The electrochemical cell is based on the technology of sodium ion-conducting ceramics and is coupled with a liquid-liquid extraction process, performed by an unconventional device, the “through-liquid-exchanger.” Our technique bypasses the bottleneck of other similar techniques by working with solutions at very high concentrations. Our initial experiments prove an unprecedented energy efficiency (ratio between the electrical work produced and the incoming heat necessary to restore the initial solutions concentrations) of 3% from a heat source <100°C and a power density of 10 W/m², with the possibility of further improvements.

从低温热源（<100°C）收集能量将能够利用当前尚未开发的可再生资源。最近提出的技术无法达到合适的效率。我们在这里提出一种氧化还原液流电池，该电池可以通过热处理，蒸馏进行充电。电化学电池从两种不同浓度的碘化钠水溶液的混合自由能中产生电能。电化学电池基于传导钠离子的陶瓷技术，并结合了由非常规设备“液体直通交换器”执行的液-液萃取过程。我们的技术通过使用非常高浓度的溶液来绕开其他类似技术的瓶颈。²，具有进一步改进的可能性。