Ultralight and hydrophobic MXene/chitosan-derived hybrid carbon aerogel with hierarchical pore structure for durable electromagnetic interference shielding and thermal insulation

Abstract

Lightweight, robust and durable high-performance electromagnetic interference (EMI) shielding materials with excellent thermal insulation properties are highly desired for modern integrated electronic systems used in military and aerospace applications. Although MXenes have exhibited high shielding performance, it remains a great challenge to build high-performance EMI shielding MXene-based aerogels with minimal MXene content and high durability. Here, hierarchically porous hybrid carbon aerogels have been constructed by assembling chitosan (CS) hydrogels and MXenes via freeze-drying followed by a suitable heat treatment strategy. Due to the special MXene–TiO2–C heterostructures and high conductivity resulting from heating at 800 °C under an Ar atmosphere, an ultralight hybrid carbon aerogel (11.9 mg cm−3) with 0.1322 vol% MXene exhibits a high EMI shielding effectiveness (EMI SE) of ∼61.4 dB and a specific SE of 5155.46 dB cm3 g−1 at a thickness of ∼3 mm. Furthermore, the hybrid carbon aerogel also provides significant thermal insulation (∼25.88 mW m−1·K−1 at 25 °C and ∼62.65 mW m−1·K−1 at 800 °C under Ar) as well as fire resistance. Superior EMI shielding and thermal insulation performance can be retained even after storage in a hygrothermal environment for 30 days, which guarantees long-term application of the hybrid carbon aerogel in humid or high-temperature environments.