In Situ Spatially Confined Silver Nanoparticles in 3D Laser‐Induced Graphene Architecture for All‐in‐One Planar Supercapacitor‐Glucose Sensor System

Self-powered integrated systems that leverage micro-supercapacitors as power sources for sensors are vital for portable and wearable electronics; however, they often encounter compatibility issues arising from bifunctional active materials that enable high energy storage capacity and sensing performance. Herein, a spatial confinement approach is proposed for designing in situ-encased silver nanoparticles within a 3D porous laser-induced graphene framework (LIG/Ag), which serves as a bifunctional active material for all-in-one supercapacitor-sensor systems. Such engineered LIG/Ag features ample pseudocapacitive active sites, high electrical conductivity, and fast ion diffusion channels, which favor high reaction kinetics and electrode material utilization, significantly improving its electrochemical reactivity. Flexible symmetric supercapacitors (FCSs) assembled with an optimized LIG/Ag achieve a high energy density of 0.27 µWh cm^-2, with a capacitance retention of 92.6% after 10 000 cycles, as well as good mechanical stability. Furthermore, a flexible three-electrode (FTE) assembled with the optimized LIG/Ag exhibits a glucose detection sensitivity of 405.24 µA mM^-1 cm^-2 and a fast response time of less than 1 s. As a proof-of-concept, a flexible, planar, self-powered glucose detection system with a LIG/Ag hybrid serving as a bifunctional active material delivers favorable capacitive properties and high glucose sensitivity, demonstrating its feasibility for glucose concentration monitoring.