Gel-Based Ionic Circuits

Ionic circuits have emerged as a promising candidate to bridge the gap between biological and artificial systems by applying the mechanically compliant and adaptive nature of gels as ionic conductors. Gel-based ionic circuits exploit the intrinsic characteristics of ions, such as their mass, diversity, and local accumulation, to achieve selectivity, hysteresis, and chemical-electric signal transduction. Their dynamic and nonlinear behaviors not only emulate traditional solid-state electronic systems but also exhibit unique functionalities and operating mechanisms extending beyond established electronic paradigms. In this review, we categorize gel-based ionic circuits into four major functional classes: passive circuit elements, active circuit elements, power sources, and noncircuit elements. We comprehensively discuss the fundamental operating principles, materials strategies, and curren…