ScholarWorks@성균관대학교

초록

The performance of hydrogel electrolytes is strongly related to their structure-property relationships and interactions with other materials, determining ionic conductivity, mechanical stability, operating voltage, and electrochemical performance in flexible supercapacitor (SC) applications. Here, we incorporate polyanionic alginate into a polyacrylamide hydrogel followed by immersion in electrolytes of varying concentrations to form polyanionic hydrogel electrolytes. The carboxylate groups within the hydrogel network facilitate ion transportation while restricting water activity, preventing water decomposition at high voltages, and expanding the SC voltage window. This study evaluates SCs using bamboo-derived hierarchical porous carbons (BHPCs) and commercial charcoal-derived activated carbons (ACs) with various polyanionic hydrogel electrolytes. The optimized hydrogel electrolyte, containing calcium chloride, effectively enables SC operation within a 1.6 V voltage window, overcoming low voltage limitation of conventional hydrogel electrolytes. This SC delivers a high-level energy density of 21.68 Wh kg−1, a power density of 400 W kg−1, excellent longevity, and electrochemical stability under mechanical deformations. Most importantly, the integration of renewable and scalable BHPC with low-cost polyanionic alginate hydrogel electrolyte marks the as-prepared SC as a standout in the carbon-based flexible SC technology. Overall, this work contributes to developing functional hydrogel electrolytes through structural manipulation, paving the way for advanced energy storage devices. © 2025

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