Thermogalvanic and Thermocapacitive Behavior of Superabsorbent Hydrogels for Combined Low-Temperature Thermal Energy Conversion and Harvesting
Thermogalvanic and Thermocapacitive Behavior of Superabsorbent Hydrogels for Combined Low-Temperature Thermal Energy Conversion and Harvesting
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DOI：
10.1021/acsaem.1c02060
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发表时间：
2021-09-13
影响因子：
6.4
通讯作者：
Aldous, Leigh
中科院分区：
文献类型：
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作者：
Buckingham, Mark A.;Zhang, Shuai;Aldous, Leigh
社会产生的能量中约有三分之二作为废热损失掉了。热电原电池可以连续地将热能直接转化为电能。相反，热电容可以转换和存储热能作为热电容。在这里，我们报道了通过容器模板合成设计的两种高吸水性整体聚合物水凝胶基质，它们作为高浓度氧化还原活性离子(即[Fe(CN)（6)]（3-/4-）和Fe2+/3+）的软宿主材料。这些高电荷的高吸水性水凝胶被发现可以改善负载氧化还原对的电催化和欧姆电阻，防止电解质泄漏，并能够同时进行热电转换和热容存储。未优化的最大热电功率密度约为95 mW m(-2) (δ T为20 K)，与其他已报道的凝胶系统相当。优化后的热电容密度约为220 F cm(-2)，比之前报道的最高密度高15倍。因此，这些新系统为低品位废热的收集和储存提供了新的可能性。
Around two-thirds of the energy generated by the society is lost as waste heat. Thermogalvanic cells can continuously convert thermal energy directly into electrical energy. Conversely, thermocapacitors can convert and store thermal energy as thermocapacitance. Here, we report two superabsorbent monolithic polymer hydrogel matrices designed through vessel-templated synthesis, which act as soft host materials for extremely high concentrations of redox-active ions, namely, [Fe(CN)(6)](3-/4-) and Fe2+/3+. These highly charged superabsorbent hydrogels were found to improve both electrocatalysis and ohmic resistance of the hosted redox couples, preventing electrolyte leakage, and enable the ability to perform both thermogalvanic conversion and thermocapacitive storage. An unoptimized maximum thermogalvanic power density was observed at ca. 95 mW m(-2) (Delta T of 20 K), on par with other reported gelled systems. An optimized thermocapacitance density of ca. 220 F cm(-2) was achieved, which is 15-fold higher than the highest previously reported. These novel systems therefore present new possibilities in both the harvesting and storage of low-grade waste thermal energy.