Monolithic Self-Supported MXene/Aramid Nanofiber/Ag Nanoparticle/MXene Composite Membranes for Integrated EMI Shielding, Joule Heating, and Energy Storage

Achieving high-performance flexible electronics requires material systems capable of unifying mechanical resilience with multifunctional properties such as electrical conductivity and thermal management. In this study, a monolithic, self-supporting composite membrane with an interpenetrating network of MXene, aramid nanofiber (ANF), and Ag nanoparticles was successfully fabricated via a one-step process that integrates vacuum-assisted filtration with in situ redox assembly. In this integrated architecture, ANFs form a robust mechanical scaffold. MXene nanosheets establish a foundational conductive network. Critically, the in situ formed AgNPs act as conductive bridges, electrically interconnecting the MXene sheets to significantly enhance the overall electrical conductivity. The sequential addition protocol, finalized with extra MXene, optimizes this ternary network by enhancing dispersion and interfacial compatibility, yielding a stable, synergistic structure. Benefiting from multilevel interfacial synergy, the resulting 40 μm-thick monolithic membrane integrates multiple high-performance functions, an EMI shielding effectiveness of 48 dB, rapid Joule heating up to 210 °C within 20 s at a low voltage of 1.5 V, and notable electrochemical activity. When used as a freestanding electrode for zinc-ion storage, it delivers an areal capacity of 1.7 mAh cm–2 with remarkable rate capability. This work establishes a scalable, integrated fabrication strategy, offering a robust platform for next-generation applications in wearable electronics, thermal management, and microenergy systems.