Liquid-state thermocells (LITCs) have a promising for efficient low-grade waste heat harvesting. However, its practical application is restricted by low ionic thermopower and normalized maximum power density (Pmax/∆T2) due to the limits of ionic reaction and transport processes. Here, we demonstrate a liquid-flow thermocell (LFTC) with giant thermoelectric performance by inducing hybrid entropy increasing. The LFTCs consists of a Y-shaped microchannel and the flowing equimolar oxidant/reductant electrolyte injected separately from the Y-shaped inlet, respectively. During mixing of oxidant and reductant in microchannel, it can induce the interaction of redox ions and surrounding solvation, and thus increase its entropy difference of solvation structure, synergistically enhancing the thermogalvanic effect and mass transfer of redox ions. This can effectively break through the limits of ionic reaction/transport dynamics and thermodynamics processes, and reach a giant ionic thermopower of −21.5 mV K−1, which is 13 times larger than that of pristine LITCs. The high hybrid entropy change can boost the Pmax/∆T2 of LFTCs into the highest value of 16.5 mW m−2 K−2 until now, much higher than the previous records of LITCs. LFTCs with cost effectiveness have a great potential to realize efficient heat-to-electricity conversion.

中文翻译：

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用于低级热量收集的具有高混合熵的液流热电池


液态热电池（LITC）在高效低品位废热收集方面具有广阔的前景。然而，由于离子反应和输运过程的限制，其实际应用受到低离子热电势和归一化最大功率密度（Pmax/ΔT2）的限制。在这里，我们通过诱导混合熵增加展示了具有巨大热电性能的液流热电池（LFTC）。 LFTC 由 Y 形微通道和分别从 Y 形入口单独注入的流动等摩尔氧化剂/还原剂电解质组成。氧化剂和还原剂在微通道中混合时，可以诱发氧化还原离子与周围溶剂化物的相互作用，从而增大其溶剂化结构的熵差，协同增强氧化还原离子的热电偶效应和传质。这可以有效突破离子反应/输运动力学和热力学过程的极限，达到-21.5 mV K−1的巨离子热电势，比原始LITC大13倍。高混合熵变可以将 LFTC 的 Pmax/ΔT2 提高到迄今为止的最高值 16.5 mW m−2 K−2 ，远高于 LITC 的先前记录。具有成本效益的LFTC在实现高效热电转换方面具有巨大潜力。