Cellulose-based Ionic Conductive Hydrogels with Tunable Flexibility and Ionic Conductivity for Multifunctional Applications in Flexible Electronics
Abstract
Wearable sensors and flexible energy storage devices impose distinct requirements on ionic conductive hydrogels, particularly regarding the balance between flexibility and conductivity. However, existing hydrogels lack a simple and scalable approach to tailor these properties for targeted applications, meeting the requirements of different applications. Here, we propose a strategy to regulate the microstructure of cellulose-based ionic conductive hydrogels (ICH) by leveraging competitive hydration effects between Zn2+ and Li+ ions, enabling single-step performance tuning. When Zn2+ dominates (ICH-1), hydrated ions expand cellulose chain spacing, enhancing ion mobility and yielding good conductivity (18.48 mS·cm-1). The resulting asymmetric flexible capacitor (ICH-1) achieves a 0-2.0 V voltage window, with exceptional energy density (50.6 Wh·kg-1) and power density (1000.1 W·kg-1). Conversely, Li+-dominant ICH-3 exhibits compact cellulose chains, endowing good flexibility (311.84 kPa at 35% strain), ionic conductivity (13.16 mS·cm-1) and sensitive electromechanical performance (GF=2.78). This enables its application as a biomimetic e-skin sensor for real-time human motion monitoring and human-computer interaction. Our method addresses the limitations of conventional ICH fabrication, offering scalable production and demonstrating significant industrial potential.