SnS2@Conducting Energy Level-Induced Functionalized Boron Nitride for an Asymmetric Supercapacitor

Large-volume oscillations, poor stability, and low inherent conductivity of bare SnS2 cause poor charge storage capacity, not expected for supercapacitor devices. In this study, we demonstrate an in situ growth of SnS2 on functionalized boron nitride (m(K)-BN)/carbon nanotube (CNT) using a facile template-free hydrothermal method to introduce supplementary energy levels for electron transport, appropriate for an electrochemical device. Facile surface functionalization on BN provides the additional conducting energy levels for improved charge storage mechanism. Compounding of BN and SnS2 improves the pseudocapacitive contribution of the electrode through a redox reaction as well as stability. Layered BN and CNT can alter the surface texture and surface area of the electrodes, which is important for the charge storage mechanism. X-ray photoelectron spectroscopy and X-ray diffraction analyses confirm the formation of composites, possible interactions among the individual components, and intercalation of layered materials. In the three-electrode electrochemical study, SnS2/mK-BN/CNT reveals a specific capacitance of 433 F/g in an aqueous electrolyte. An asymmetric supercapacitor device is fabricated using SnS2/m(K)-BN/CNT and 1 M TEABF4/dimethyl sulfoxide as the cathode and the electrolyte, respectively. The device exhibits the maximum specific capacitance of 87 F/g and an energy density of 49 W h/kg with 101% cyclic stability. Supplementary energy levels realized through the smart combination of SnS2, mK-BN, and CNT make SnS2/ m(K)-BN/CNT perfect for a supercapacitor and will open avenues for next-generation applications of this SnS2-based composite material for advanced supercapacitors.