Efficient harvest of low-grade waste heat in the environment through thermoelectric materials represents a promising strategy to address the current energy crisis. In practical applications, the mechanical properties of thermoelectric materials are crucial for their lifespan and operational environment. In this study, we designed a series of ionic thermoelectric hydrogels, PAM/CMC-xLiCl, with high mechanical properties. These hydrogels are formed by a dual network structure composed of polyacrylamide (PAM) and sodium carboxymethyl cellulose (CMC), with LiCl serving as the conductive material. At room temperature, the optimal Seebeck coefficient and ionic conductivity of the hydrogels can reach 2.96 mV K−1 and 36.51 mS cm−1, respectively. Based on the physical entanglement, hydrogen bonding, and chemical crosslinking of the polymer chains within the ionic hydrogels, which demonstrate outstanding mechanical properties (elongation at break >1300 %, fracture toughness >1700 kJ m−3), maintaining 95 % resilience under a large strain of 400 %. Furthermore, due to the hydration properties of LiCl, the ionic hydrogels exhibit excellent freeze resistance and the capability to absorb moisture for self-regeneration upon drying. Lastly, the fabricated ionic thermoelectric supercapacitor can generate a thermoelectric voltage of 0.182 V under a ΔT of 12 K, with a power density of 6.68 mW m−2, showing promising prospects for application in waste heat harvest fields.

中文翻译：

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高度可拉伸、低滞后和防冻水凝胶，用于离子热电超级电容器中的低品位热能收集


通过热电材料有效收集环境中的低品位余热是解决当前能源危机的一种有前途的策略。在实际应用中，热电材料的机械性能对其使用寿命和操作环境至关重要。在这项研究中，我们设计了一系列具有高机械性能的离子热电水凝胶 PAM/CMC-xLiCl。这些水凝胶由聚丙烯酰胺 （PAM） 和羧甲基纤维素钠 （CMC） 组成的双网络结构形成，其中 LiCl 用作导电材料。在室温下，水凝胶的最佳塞贝克系数和离子电导率分别可以达到 2.96 mV K-1 和 36.51 mS cm-1。基于离子水凝胶内聚合物链的物理纠缠、氢键和化学交联，表现出出色的机械性能（断裂伸长率 >1300 %，断裂韧性 >1700 kJ m-3），在 400 % 的大应变下保持 95% 的弹性。此外，由于 LiCl 的水合特性，离子水凝胶表现出优异的抗冻性和吸收水分在干燥后自我再生的能力。最后，所制备的离子热电超级电容器可在 12 K 的 ΔT 下产生 0.182 V 的热电电压，功率密度为 6.68 mW m−2，在余热收集领域显示出广阔的应用前景。