Development of cohesive exfoliated h-BN-CuS nanosheets through an ultrasonic approach for hybrid supercapacitors

Abstract

An enticing aspect of supercapacitors is their advantages of high power density, long cycle life, and quick charging capabilities. Two-dimensional electrode materials can extensively improve their energy density owing to their advantages of layered morphology, large surface area, and tunable bandgap. In this work, exfoliated h-BN-CuS nanocomposites (Exd h-BN-CuS NCs) were designed and synthesized using an inexpensive ultrasonic approach. Furthermore, their chemical composition, vibrational modes, morphology, and phase formation were thoroughly characterized and analysed. Additionally, their electrochemical characterization was conducted in a three-electrode system, revealing a battery-type characteristic and achieving a capacity of 543.7 C g⁻¹ at 10 A g⁻¹. Furthermore, a hybrid supercapacitor (HSC) device of Exd h-BN-CuS//activated carbon was developed. It consisted of activated carbon (AC) as the negative electrode, which bestowed good electrical conductivity, and the Exd h-BN-CuS NCs with a cohesive nanosheet morphology as the positive electrode. The HSC device exhibited a superior specific capacity of 234.6 C g⁻¹ at 2 A g⁻¹ and a high energy density (E_De) of 55.07 Wh kg⁻¹ at a power (P_De) density of 1689.98 W kg⁻¹. Furthermore, it sustained cyclic stability over 5000 GCD cycles at an applied current density of 10 A g⁻¹, showing 87.5% capacitive retention.