Thermoelectric conversion of low temperature, delocalized and abun-dant thermal sources is crucial for the development of the Internet of the Things (IoT) and/or carbon free society. Thermocells, or ther-mo-electrochemical cells, are of great interest in thermoelectric con-version of low-temperature heat due to the low cost and flexibility of components. However, significant improvement of the conversion efficiency is required for the practical use of the cells. Here, we report thermocells driven by volume phase transition (VPT) of hydrogel nanoparticles (NPs). Entropically driven VPT of poly(N-isopropylacrylamide) NPs containing carboxylic acids and amines generates a pH gradient of up to 0.049 pH K-1 and -0.053 pH K-1, respectively, around physiological temperature. The pH gradient triggers the proton-coupled electron transfer (PCET) reactions of quinhydrone on the electrodes, resulting in the highly efficient ther-moelectric conversion with a Seebeck coefficient (Se) of -6.7 mV K-1 and +6.1 mV K-1. Thermocells driven by phase transition of hydrogels provide a non-toxic, flexible and inexpensive charger that harvests carbon free energy from abundant energy sources such as the solar, body and waste heat.

中文翻译：

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由水凝胶纳米颗粒的相变驱动的热电池

低温、离域和丰富的热源的热电转换对于物联网 (IoT) 和/或无碳社会的发展至关重要。由于组件的低成本和灵活性，热电池或热电化学电池在低温热的热电转换方面非常受关注。然而，电池的实际应用需要显着提高转换效率。在这里，我们报告了由水凝胶纳米粒子 (NP) 的体积相变 (VPT) 驱动的热电池。含有羧酸和胺的聚（N-异丙基丙烯酰胺）NP 的熵驱动 VPT 在生理温度附近分别产生高达 0.049 pH K-1 和 -0.053 pH K-1 的 pH 梯度。pH 梯度会触发醌氢酮在电极上的质子耦合电子转移 (PCET) 反应，从而实现高效的热电转换，塞贝克系数 (Se) 为 -6.7 mV K-1 和 +6.1 mV K-1 . 由水凝胶相变驱动的热电池提供了一种无毒、灵活且廉价的充电器，可从丰富的能源（如太阳能、身体和废热）中收集无碳能量。