Theoretical and Experimental Insights into Multifunctional Energy Storage and Iontronic Capacitive Pressure Sensing Based on Hierarchical Porous Framework

Natural-drying graphene aerogel (GA) with hierarchical porous framework architecture has been prepared, providing excellent mechanical and electrochemical properties. When used as electrode material for supercapacitors, GA achieves excellent capacitance of 240 F g−1 at a current density of 0.2 A g−1. Also, GA can provide a high energy density of 21.0 Wh kg−1 at a power density of 79 W kg−1. In addition, an iontronic capacitive pressure sensing based on PVA-H2SO4//graphene aerogel//PVA-H2SO4 sandwich structure has been developed. The iontronic capacitive sensor exhibits high capacitive response, outstanding sensitivity (0.54 kPa−1), fast response time (120 ms), and remarkable cyclic stability (1000 cycles). Additionally, the theoretical analysis based on pressure sensing and energy storage indicates that compressive strain and initial energy density are closely related to sensitivity, while the simulation illustrates that compressive strain and initial energy density exhibit a positive influence on achieving high sensitivity. In application, the multifunctional device demonstrates high potential in wearable energy storage and sensor electronics.