Ruano Guillem, Iribarren José I, Pérez-Madrigal Maria M, Torras Juan, Alemán Carlos
Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, Campus Diagonal Besòs (EEBE), C/Eduard Maristany, 10-14, 08019 Barcelona, Spain.
Barcelona Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, Campus Diagonal Besòs (EEBE), C/Eduard Maristany, 10-14, 08019 Barcelona, Spain.
Polymers (Basel). 2021 Apr 19;13(8):1337. doi: 10.3390/polym13081337.
Flexible hydrogels are attracting significant interest as solid-like electrolytes for energy storage devices, especially for supercapacitors, because of their lightweight and anti-deformation features. Here, we present a comparative study of four ionic conductive hydrogels derived from biopolymers and doped with 0.1 M NaCl. More specifically, such hydrogels are constituted by κ-carrageenan (κC), carboxymethyl cellulose (CMC), poly-γ-glutamic acid (PGGA) or a phenylalanine-containing polyesteramide (PEA). After examining the morphology and the swelling ratio of the four hydrogels, which varies between 483% and 2356%, their electrical and capacitive behaviors were examined using electrochemical impedance spectroscopy. Measurements were conducted on devices where a hydrogel film was sandwiched between two identical poly(3,4-ethylenedioxythiophene) electrodes. The bulk conductivity of the prepared doped hydrogels is 76, 48, 36 and 34 mS/cm for PEA, PGGA, κC and CMC, respectively. Overall, the polyesteramide hydrogel exhibits the most adequate properties (i.e., low electrical resistance and high capacitance) to be used as semi-solid electrolyte for supercapacitors, which has been attributed to its distinctive structure based on the homogeneous and abundant distribution of both micro- and nanopores. Indeed, the morphology of the polyestermide hydrogel reduces the hydrogel resistance, enhances the transport of ions, and results in a better interfacial contact between the electrodes and solid electrolyte. The correlation between the supercapacitor performance and the hydrogel porous morphology is presented as an important design feature for the next generation of light and flexible energy storage devices for wearable electronics.
柔性水凝胶作为储能设备，特别是超级电容器的类固体电解质，因其轻质和抗变形特性而备受关注。在此，我们对四种由生物聚合物衍生并掺杂0.1 M氯化钠的离子导电水凝胶进行了比较研究。更具体地说，此类水凝胶由κ-卡拉胶（κC）、羧甲基纤维素（CMC）、聚γ-谷氨酸（PGGA）或含苯丙氨酸的聚酯酰胺（PEA）构成。在考察了四种水凝胶的形态和溶胀率（溶胀率在483%至2356%之间变化）之后，使用电化学阻抗谱对其电学和电容行为进行了研究。测量是在将水凝胶薄膜夹在两个相同的聚（3,4-乙撑二氧噻吩）电极之间的器件上进行的。所制备的掺杂水凝胶的体积电导率，PEA、PGGA、κC和CMC分别为76、48、36和34 mS/cm。总体而言，聚酯酰胺水凝胶表现出最适合用作超级电容器半固体电解质的特性（即低电阻和高电容），这归因于其基于微孔和纳米孔均匀且丰富分布的独特结构。实际上，聚酯酰胺水凝胶的形态降低了水凝胶电阻，增强了离子传输，并导致电极与固体电解质之间有更好的界面接触。超级电容器性能与水凝胶多孔形态之间的相关性被视为下一代可穿戴电子产品轻质柔性储能设备的重要设计特征。
