有鑑於大多數水凝膠電解質固有的機械強度較差，無法滿足穿戴式裝置中多功能超級電容的要求，因此在本研究中，研究具有正負離子對的水膠電解質，以了解高性能和柔性超級電容的可行性。首先，透過一鍋法光聚合一系列含有2-甲基丙烯酸羥乙酯 (HEMA)、帶四級銨根正電荷的單體 META、帶磺酸根負電荷的單體 AMPS 和交聯劑 PEGDA的 HAS水凝膠電解質。後續利用FTIR與TGA分析HAS電解質的官能基與熱穩定性，且為了在電化學表現與機械強度中取得平衡點，透過EIS與DMA對HAS電解質的配方作探討，由於正負離子對的存在可以形成離子遷移通道，HAS4具有64.8 mS cm-1的高離子導電度，且與 HAS5相比，機械性質幾乎沒有衰退，HAS4 具有 65 %的壓縮應變與0.45 MPa的抗壓強度。
後續，使用對稱碳電極超級電容測試HAS電解質的電化學性能。 HAS4超級電容在電流密度為0.8 A g-1下，具有136.6 F g-1的高比電容、39.4 Wh kg-1的能量密度和1080.8 W kg-1的功率密度，我們透過拉曼光譜探討離子與水在HAS電解質中的狀態，進一步驗證 HAS4超級電容具備高性能的原因。令人印象深刻的是，HAS4超級電容不僅有良好電化學性能表現，更有好的電化學穩定性，在 2 A g-1 下，進行5,000 次充電/放電循環後能維持96.3 %的電容保存率，顯示HAS4的良好循環穩定性。另外，HAS4可以彎折 90°、135°和180°，而且不會造成明顯的電容損失，顯示優異的機械穩定性。因此，HAS4能作為可撓性超級電容的電解質，因為它具有卓越的機械強度與出色的電化學性能。

Due to inherently poor mechanical strength features, most of hydrogel electrolytes (HE) cannot meet the requirements of multifunctional supercapacitors (SC). In this study, HEs with immobilized pair ions (IPI) were studied for the possibility of high-performance and flexible supercapacitors (fSC). 2-hydroxyethyl methacrylate (HEMA), positive charged monomer META, negative charged monomer AMPS and crosslinker PEGDA were prepared to synthesize five polymeric samples from HAS1 to HAS5 with increasing HEMA amount via one-pot copolymerization. HAS hydrogel electrolytes were obtained by soaking polymeric samples in 5 m NaClO4. HAS4 exhibited a high ionic conductivity of 64.8 mS cm-1 in EIS due to the presence of IPIs while the mechanical properties were nearly unchanged compared to HAS5. HAS4 showed an excellent compressive strain of 65 % and compressive strength of 0.45 MPa in DMA. We further analyzed the ClO4- ion interactions in HAS electrolytes by Raman spectroscopy. Hydrogel electrolytes with more proportion of free anions (FA) and less contact ion-pair (CIP) render higher ionic conductivity, which was consistent with EIS results. For the convenience of comparison, HAS1, HAS4, and HAS5 sandwiched with symmetric carbon-based electrodes were selected for electrochemical studies. Among them, HAS4 covers both electrochemical and mechanical requirements. HAS4 supercapacitor possessed a high specific capacitance of 136.6 F g-1, energy density of 39.4 Wh kg-1 and power density of 1080.8 W kg-1 at the current density of 0.8 A g-1 with 96.3 % capacitance retention after 5,000 charge/discharge cycles at 2 A g-1. Impressively, HAS4 SC can be bent at 90˚, 135˚ and 180˚ without significant capacitance loss. As a result, HAS4 may be a notable electrolyte candidate for fSCs because of its remarkable flexibility and great electrochemical performances.

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