Sustainable Hydrofluoric-Acid-Free Synthesis of MXene-Integrated Conductive Textiles for Efficient Low-Voltage Joule Heating

Flexible and efficient Joule-heating textiles are essential for next-generation wearable electronics, thermotherapy, and personal thermal management systems. In this work, we report a greener, scalable strategy to enhance the energy conversion efficiency of conductive textiles via a synergistic dual coating of polypyrrole (PPy) and MXene (Ti₃C₂T_x). MXene was synthesised from Ti₃AlC₂ using an environmentally benign hydrothermal etching method with ammonium fluoride (NH₄F), avoiding the use of hazardous hydrofluoric acid. The conductive fabrics were fabricated via in situ chemical polymerisation of PPy on silk, viscose, and cotton substrates, followed by nip-and-dip coating with exfoliated MXene nanosheets. Structural characterisation confirmed the successful formation of MXene and its uniform deposition on textile fibres. The incorporation of MXene significantly reduced surface resistivity and improved electrical conductivity across all substrates, with silk exhibiting the lowest resistivity (261 Ω/□). Joule-heating performance demonstrated excellent voltage–temperature linearity (R² > 0.97), rapid thermal response, and stable cyclic heating behaviour. PPy + MXene-coated silk reached a maximum temperature of ~ 140 °C at a low operating voltage (5 V) and exhibited superior heating rates compared to viscose and cotton. Notably, the energy conversion efficiency increased from 19.86% for PPy-coated silk to 23.92% after MXene incorporation, highlighting the strong synergistic effect between PPy and MXene in facilitating charge transport and heat generation. Pore-size analysis revealed partial pore blockage after coating, while retaining adequate fabric breathability. Overall, this study demonstrates a sustainable route to fabricate high-performance Joule-heating textiles, with PPy + MXene-coated silk emerging as a promising candidate for wearable heaters, smart textiles, and personal thermal management applications.