Wi Sung Min, Kim Jihong, Lee Suok, Choi Yu-Rim, Kim Sung Hoon, Park Jong Bae, Cho Younghyun, Ahn Wook, Jang A-Rang, Hong John, Lee Young-Woo
Department of Energy Systems Engineering, Soonchunhyang University, Asan-si 31538, Korea.
Jeonju Centre, Korea Basic Science Institute, Jeonju 54907, Korea.
Nanomaterials (Basel). 2021 Nov 11;11(11):3027. doi: 10.3390/nano11113027.
To effectively improve the energy density and reduce the self-discharging rate of micro-supercapacitors, an advanced strategy is required. In this study, we developed a hydroquinone (HQ)-based polymer-gel electrolyte (HQ-gel) for micro-supercapacitors. The introduced HQ redox mediators (HQ-RMs) in the gel electrolyte composites underwent additional Faradaic redox reactions and synergistically increased the overall energy density of the micro-supercapacitors. Moreover, the HQ-RMs in the gel electrolyte weakened the self-discharging behavior by providing a strong binding attachment of charged ions on the porous graphitized carbon electrodes after the redox reactions. The micro-supercapacitors with HQ gel (HQ-MSCs) showed excellent energy storage performance, including a high energy volumetric capacitance of 255 mF cm at a current of 1 µA, which is 2.7 times higher than the micro-supercapacitors based on bare-gel electrolyte composites without HQ-RMs (b-MSCs). The HQ-MSCs showed comparatively low self-discharging behavior with an open circuit potential drop of 37% compared to the b-MSCs with an open circuit potential drop of 60% after 2000 s. The assembled HQ-MSCs exhibited high mechanical flexibility over the applied external tensile and compressive strains. Additionally, the HQ-MSCs show the adequate circuit compatibility within series and parallel connections and the good cycling performance of capacitance retention of 95% after 3000 cycles.
为有效提高微型超级电容器的能量密度并降低其自放电率，需要一种先进的策略。在本研究中，我们开发了一种用于微型超级电容器的基于对苯二酚（HQ）的聚合物凝胶电解质（HQ-凝胶）。凝胶电解质复合材料中引入的HQ氧化还原介质（HQ-RMs）发生额外的法拉第氧化还原反应，并协同提高了微型超级电容器的整体能量密度。此外，凝胶电解质中的HQ-RMs在氧化还原反应后通过在多孔石墨化碳电极上提供带电离子的强结合附着来减弱自放电行为。具有HQ凝胶的微型超级电容器（HQ-MSCs）表现出优异的储能性能，包括在1 μA电流下具有255 mF cm的高能量体积电容，这比基于不含HQ-RMs的裸凝胶电解质复合材料的微型超级电容器（b-MSCs）高2.7倍。与2000 s后开路电位降为60%的b-MSCs相比，HQ-MSCs表现出相对较低的自放电行为，开路电位降为37%。组装后的HQ-MSCs在施加的外部拉伸和压缩应变下表现出高机械柔韧性。此外，HQ-MSCs在串联和并联连接中显示出足够的电路兼容性，并且在3000次循环后电容保持率为95%，具有良好的循环性能。
