Efficient microwave absorption with Vn+1CnT MXenes

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 % Vn+1CnTx can absorb 90% of electromagnetic waves covering the entire X band. In addition, pure Vn+1CnTx 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 Vn+1CnTx MXenes. This study points toward a new frontier for development of thin and highly absorbing MXene-based electromagnetic protection materials.