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

## TL;DR

This paper introduces a self-powered smart insole made from a new graphene-MXene composite that can monitor foot health continuously and sustainably.

## Contribution

The novel use of lignocellulose-derived LIG@MXene enables a multifunctional, self-powered wearable sensor with high performance and low environmental impact.

## Key findings

- The LIG@MXene composite achieved an electrical conductivity of 17.2 Ω∙sq−1 and structural stability.
- The insole integrates a TENG with 35 V cm−2 output, a supercapacitor with 71.4 mF cm−2 capacitance, and sensors for pressure, humidity, and sweat composition.
- The device detected L-tyrosine in sweat at a minimum concentration of 9.60 µM and emitted only 9.10 kg CO2 eq during manufacturing.

## 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 CO2 eq during manufacturing. The direct laser‐patterned synthesis of LIG@MXene composite represents a significant step forward in advancing smart wearable electronic devices.

This study presents a high‐performance foot‐monitoring platform based on lignocellulose‐derived laser‐induced MXenecomposited graphene hybrids (LIG@MXene). The LIG@MXene exhibits markedly improved electrical conductivity, structural stability, and multifunctionality, enabling integrated energy harvesting, sensing, Joule heating, and supercapacitor storage. The material enables continuous monitoring of foot pressure, humidity, and sweat biochemistry, offering strong support for sustainable wearable health technologies.