Due to the rapid development of the textile industry and increased consumption of various textiles composed of both synthetic and natural fibers, large amounts of textile waste are produced, leading to environmental and economic problems on a global scale. Turning textile waste into carbon materials that can be used in a broad range of applications has become a viable solution to address this challenge in terms of sustainability and value generation. Natural and synthetic textile fibers have distinctive molecular structures with relatively high carbon content and variable chemical functionality; therefore, they have been identified as highly promising precursors for fabricating carbon materials with various electrochemical and environmental applications. At the same time, the properties of carbonized and activated textile fibers are strongly dependent on the molecular transformations taking place during thermal treatment and functionalization of textile fibers. This review will provide a comprehensive overview of the molecular evolution of natural and synthetic textile fibers during carbonization and activation processes in terms of dehydration, depolymerization, aromatization, heteroatom preservation, and graphitization mechanisms. The effect of precursor chemical composition, pyrolysis conditions, activation process, and heteroatom incorporation on the structure of carbonized and activated textile fibers and their physical and electrochemical properties will be analyzed. Particular emphasis is placed on electrochemical applications, including capacitive deionization, supercapacitors, electrocatalysis, and emerging smart electrochemical textile systems, highlighting how molecular transformation, pore engineering, and surface chemistry govern charge storage, ion adsorption, and catalytic behavior. In addition, major characterization techniques such as Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller surface area analysis will be reviewed and discussed in relation to understanding the interdependence between molecular structure and material properties. Finally, recent issues related to feedstock heterogeneity, scalability, energy efficiency, and sustainability of processing are highlighted, and future perspectives on multifunctional carbon structures and circular utilization of textile waste are discussed.

Smart textiles have progressed from conventional passive sensing fabrics to advanced cyber-physical systems capable of integrating sensing, actuation, computation, and wireless communication within a single textile platform. With a focus on circular economy principles, this review critically examines intelligent textile ecosystems, from material architectures to AI-enabled wearable platforms. The functional hierarchy involves passive (sensing), active (sensing + response) and ultra-smart (autonomous decision making) textiles. The four classes of materials are metallic conductors, carbonaceous nanomaterials (CNTs and graphene), conductive polymers (PEDOT:PSS) and bio-based alternatives. Integration is achieved through coating, weaving, printing and additive manufacturing. Energy autonomy is achieved by five harvesting mechanisms: piezoelectric (1–10 µW·cm⁻²), triboelectric (10–100 µW·cm⁻²), thermoelectric (20–50 µW·cm⁻²), photovoltaic (100–1000 µW·cm⁻²) and bio-electrochemical (1–5 µW·cm⁻²). Hybrid systems can run continuously. Flexible supercapacitors and thin-film batteries are used for energy storage. The combination of AI and IoT allows for multi-tier architectures that encompass edge processing (TinyML), gateway management, and cloud analytics. On-device inference reduces energy consumption by 60–80%, improves privacy and enables real-time anomaly detection using CNNs, LSTMs and autoencoders. Sustainability is considered through life-cycle assessment, which quantifies impacts across extraction, fabrication, use, and end-of-life of materials. Circular strategies such as design for disassembly, harmonization of materials, biodegradable electronics, and recycling routes are all important. We critically evaluate key challenges such as manufacturing scalability, washability, biocompatibility, and regulatory standardization. This review provides a unifying framework that connects materials science, electronics, AI and sustainable design, providing a roadmap for circular, intelligent and energy-autonomous textile systems in line with UN SDGs (3, 9, 12, 13).

Smart textiles have progressed from conventional passive sensing fabrics to advanced cyber-physical systems capable of integrating sensing, actuation, computation, and wireless communication within a single textile platform. With a focus on circular economy principles, this review critically examines intelligent textile ecosystems, from material architectures to AI-enabled wearable platforms. The functional hierarchy in-volves passive (sensing), active (sensing + response) and ultra-smart (autonomous deci-sion-making) textiles. The four classes of materials are metallic conductors, carbonaceous nanomaterials (CNTs and graphene), conductive polymers (PEDOT:PSS) and bio-based alternatives. Integration is achieved by coating, weaving, printing and additive manu-facturing. Energy autonomy is achieved by five harvesting mechanisms: piezoelectric (1–10 µW·cm⁻²), triboelectric (10–100 µW·cm⁻²), thermoelectric (20–50 µW·cm⁻²), photovol-taic (100–1000 µW·cm⁻²) and bioelectrochemical (1–5 µW·cm⁻²). Hybrid systems can run continuously. Flexible supercapacitors and thin-film batteries are used for energy stor-age. The combination of AI and IoT allows for multi-tier architectures that encompass edge processing (TinyML), gateway management, and cloud analytics. On-device in-ference reduces energy consumption by 60-80%, improves privacy and enables real-time anomaly detection using CNNs, LSTMs and autoencoders. Sustainability is considered by life cycle assessment, which quantifies impacts across extraction, fabrication, use, and end-of-life of materials. Circular strategies: Design for disassembly, harmonisation of materials, biodegradable electronics, and recycling routes are all important. We critically evaluate key challenges such as manufacturing scalability, washability, biocompatibility, and regulatory standardisation. This review provides a unifying framework that con-nects materials science, electronics, AI and sustainable design, providing a roadmap for circular, intelligent and energy-autonomous textile systems in line with UN SDGs (3, 9, 12, 13).