Efficient microwave absorption with Vn+1CnTx MXenes

Abstract

The availability of MXenes and other two-dimensional conductive nanomaterials with tunable surface chemistry has reshaped the field of electromagnetic protection. However, the high electrical conductivity and low dielectric loss of titanium-based MXenes lead to strong reflection of electromagnetic waves, even when combined with polymers to form composites. Here, we report on the ability of vanadium-based MXenes to provide broadband microwave absorption. Polyurethane composites with ∼2 wt % V n+1 C n T x can absorb 90% of electromagnetic waves covering the entire X band. In addition, pure V n+1 C n T x films of submicrometer thickness can provide effective electromagnetic interference shielding. The free electron transport, surface terminations, native defects, and layers arrangement in composites have profound effects on electronic and dielectric properties of V n+1 C n T x MXenes. This study points toward a new frontier for development of thin and highly absorbing MXene-based electromagnetic protection materials. • Polyurethane composites with ∼2 wt % V n+1 C n T x absorb >90% of microwaves in X band • 600-nm-thick V n+1 C n T x films provide effective electromagnetic interference shielding • The native defects and surface groups affect the microwave absorption behavior Han et al. report that vanadium-based MXenes (V 2 CT x and V 4 C 3 T x ) can provide broadband microwave absorption with ultralow filler loading in polymer matrix. The free electron transport, surface terminations, native defects, and layers arrangement significantly affect electronic and dielectric properties of V n+1 C n T x MXenes.