Biodegradable MXene-Bamboo Cellulose Paper Electrodes for Green Wearable Sensing and Exoskeleton Control

The global rise in electronic waste highlights the urgent need for green electronics that minimize environmental impact through sustainable material selection and fabrication methods. In this work, multifunctional, biodegradable paper electrodes, designated as MXN_x/B-CP, are prepared via a simple vacuum-assisted assembly of homogenized MXene (Ti₃C₂T_x) nanosheets within bamboo-derived cellulose nanofiber (CNF). These freestanding paper electrodes offer tunable electrical conductivity, mechanical flexibility, and low-cost, scalable production. To enhance their stability, the electrodes are encapsulated in a breathable, porous Ecoflex layer, which imparts waterproofing while maintaining gas permeability. Strong hydrogen bonding at the MXene-CNF interface facilitates continuous electron transport and structural integrity, yielding a nonlinear piezoresistive response with a gauge factor increasing from 3.7 to 11.42 at small strain range, alongside a strain-adaptive Young's modulus ranging from 0.064 to 1.768 MPa. Benefiting from this synergistic design, the electrodes support a wide range of sensing applications, including bending strain detection, surface electromyography, and human-machine interfaces for exoskeleton control while exhibiting excellent stability, low noise, and long-term durability under repeated deformation. This innovation not only expands the potential of paper-based electronics but also offers a scalable pathway toward sustainable, high-performance solutions for next-generation wearable and assistive technologies.