Phase interface engineering of defect-rich 1T/2H-WX2/RGO (X = S, Se) nanosheets for efficient microwave absorption and supercapacitor applications

Abstract

Phase interface engineering plays an essential role in the design and development of effective electromagnetic wave (EMW) absorption materials and energy storage devices. Nevertheless, the development of multifunctional materials that can simultaneously tackle these challenges remains a significant difficulty. In this study, we developed multifunctional defect-rich 1T/2H-WX₂/RGO (X = S, Se) nanosheets utilizing a simple solvothermal and freeze-drying technique. The synthesized 1T/2H-WX₂/RGO nanosheets exhibited superior EMW absorption and electrochemical characteristics. The effective absorption bandwidth (EAB) reached 7.68 GHz at a thickness of 3.10 mm. This excellent performance can be attributed to various loss mechanisms, including conductive loss, defect-induced dipole polarization loss and interface polarization loss. Moreover, the 1T/2H-WS₂/RGO-15 nanosheets attained a high specific capacitance of 390.44 F g⁻¹ at a current density of 1 A g⁻¹. In contrast, the 1T/2H-WSe₂/RGO-4 nanosheets demonstrated impressive cycling stability of 71.81% after 5000 cycles, which can be attributed to the active sites provided by its rich heterogeneous interface. The energy density of the 1T/2H-WS₂/RGO-15 nanosheets was measured to be 4.27 Wh kg⁻¹ at a power density of 400 W kg⁻¹. This research offers valuable insights into the development of multifunctional materials that can serve as EMW absorbers and supercapacitor electrodes.