Integrated Self‐Powered Sensors for Continuous Foot Health Monitoring via Laser‐Induced MXene‐Composited Graphene Hybrids From Lignocellulose

Abstract Intelligent wearable devices based on laser‐induced graphene (LIG) have attracted significant attention for human health monitoring. This paper proposed an innovative all‐in‐one design for preparing a self‐powered smart insole using laser‐induced MXene‐composited graphene hybrid (LIG@MXene) from lignocellulose precursor. By incorporating MXene into the LIG, the composite achieved improved crystallinity and reduced defects, contributing to the electrical conductivity (17.2 Ω∙sq −1 ) and structural stability. The optimal laser processing parameters are 55% for laser power and 70 mm s −1 for etching rate. The optimized LIG@MXene composite functions as a versatile platform for integrating triboelectric nanogenerator (TENG) with a high output power of 35 V cm −2 , supercapacitor with a superior areal capacitance of 71.4 mF cm −2 and the excellent cycling stability of 89.5% retention, Joule heater of the maximum heating temperature of 113 °C at 5 V, and various flexible sensors for pressure, humidity and sweat composition with high sensitivity and linearity. In particular, the minimum L‐tyrosine limit of detection in sweat is only 9.60 µM. These functional modules are embedded within an insole via a direct laser writing technology, which only emitted 9.10 kg CO 2 eq during manufacturing. The direct laser‐patterned synthesis of LIG@MXene composite represents a significant step forward in advancing smart wearable electronic devices.