Lightweight Nanostructures of Cellulose Nanofibers and Ti3C2Tx MXenes for Their Application in Electromagnetic Interference Shielding

MXenes, a large family of titanium carbides and nitrides, have emerged as potential electromagnetic interference (EMI) shielding materials due to their outstanding electrical properties and lightness. However, the fragility of structures constructed exclusively from these two-dimensional materials suggests the complementary use of other nanomaterials as primary building blocks, with MXenes serving as active-conductive fillers. Compared to MXenes alone, these hybrid structures demonstrate significant mechanical improvements without a significant loss of electrical properties due to the synergy between porosity and the lamellar structure. This study explores the use of biodegradable cellulose nanofibrils (CNFs) as non-active building blocks for the fabrication of nanohybrid structures. We use Ti3C2Tx MXenes as active-conductive nanofillers in a simple process where both components are dispersed and freeze-dried to produce EMI shielding aerogels. This process minimizes MXene waste while maintaining total shielding effectiveness (SET) values around 20 dB. The way in which MXenes are incorporated into the final material is crucial, and a method to optimize their properties and achieve the obtained SET values has been identified.