Double-network polyelectrolyte-based hydrogels for ionic current rectification

Recently, ionic diodes have garnered significant attention due to their potential applications in flexible electronics and implantable bioelectronics, where conventional semiconductor-based devices face inherent limitations. Here, we report a dual-network hydrogel-based ionic diode composed of polyvinyl alcohol and polyacrylamide matrices incorporating cationic polydiallyldimethylammonium and anionic poly(sodium 4-styrenesulfonate) polyelectrolytes. The system is fabricated via chemical and freeze–thaw crosslinking, achieving a synergistic balance of mechanical integrity and ionic mobility. The optimized device exhibits a very high current rectification ratio of 53.9, attributed to enhanced interfacial ion transport. This strategy enables scalable fabrication of robust ionic diodes, offering a versatile platform for next-generation ionic devices and flexible bioelectronic systems.