Effect of copper doping on the electrochemical behavior of SnS2 electrodes for aqueous Al-ion hybrid supercapacitors†

Abstract

The choice and optimization of electrode materials are crucial for maximizing the energy density and optimizing the overall performance of supercapacitors. Layered metal dichalcogenides (LMDs), such as SnS₂, are promising faradaic materials for hybrid supercapacitors due to their layered structures and abundant sites for effective charge transport. However, their performance is often limited by low electrical conductivity and poor stability owing to low ionic transport and high volumetric expansion. This study presents a straightforward method for enhancing the performance of SnS₂-based electrodes by doping with copper through a facile solid-state synthesis. The incorporation of copper doping significantly improved the specific capacitance, demonstrating a near 40% increase compared to pristine SnS₂ without any complicated optimization procedures or the need to form any composites/heterostructures. The maximum specific capacitance achieved at a current density of 1 A g⁻¹ is 98 F g⁻¹ for pristine SnS₂ and 140 F g⁻¹ for 5% Cu-doped SnS₂ in aqueous 1 M AlCl₃ electrolyte that highlights the potential of copper-doped SnS₂ as a high-performance electrode material for aqueous Al-ion supercapacitors, paving the way for further optimization and development of efficient and sustainable energy storage devices.