Fireproof ultrastrong all-natural cellulose nanofiber/montmorillonite-supported MXene nanocomposites with electromagnetic interference shielding and thermal management multifunctional applications

To shield significantly serious radiation pollution and reduce fire disasters, fire-retardant MXene-based electromagnetic interference (EMI) shielding nanocomposites featuring superb mechanical properties are highly desired, but remain a major challenge to prepare. Here, we propose a Janus structural engineering strategy to manufacture all-natural cellulose nanofiber (CNF)/montmorillonite (MMT)-supported MXene papers (CMMPs) using a sequential deposition followed by hot-pressing. Inspired by natural nacre, MMT nanosheets are incorporated into CNFs to construct a substrate layer with a “brick-mortar” layered structure that serves to provide mechanical properties, while the independent MXene layer ensures electrical conductivity. The resultant CMMPs exhibit extraordinary mechanical performances involving a mechanical strength of 272.7 MPa and Young's modulus of 10.8 GPa, high electrical conductivity, and a superb EMI shielding effectiveness of 56.1 dB and EMI SE/t of 19 140.8 dB cm−1. Moreover, the designed CMMPs possess impressive flame-retardant and electro-/photothermal heating features, demonstrating their reliability, safety, and versatility. Therefore, such high-performance CMMPs developed by a facile and sustainable preparation strategy possess substantial application prospects in EMI shielding, thermal management, and fire protection.