Unlocking high-energy and long-life supercapacitors via Zn–MnO2/MoS2 heterostructure engineering

Abstract

Materials engineering plays a pivotal role in determining the energy storage efficiency of supercapacitors. In this work, a Zn–MnO₂/MoS₂ heterostructure was synthesized via a hydrothermal route, where the synergistic coupling of Zn-doped MnO₂ with conductive MoS₂ nanosheets significantly enhanced redox activity, electronic conductivity, surface area and structural stability. Zn doping not only expanded the MnO₂ lattice to facilitate faster ion diffusion but also induced oxygen vacancies, providing additional active sites for charge storage. Meanwhile, MoS₂ offered a conductive 2D framework that buffered volume changes and accelerated electron transport. As a result, the Zn–MnO₂/MoS₂ electrode delivered a high capacitance of 1440 F g⁻¹ at 2.85 A g⁻¹, outperforming individual Zn–MnO₂ (1250 F g⁻¹) and MnO₂/MoS₂ (1370 F g⁻¹) as well as previously reported electrodes in 1 M KOH. Furthermore, the assembled Zn–MnO₂/MoS₂//AC device exhibited a specific capacitance of 147 F g⁻¹ at 2.85 A g⁻¹, an excellent energy density of 59 Wh kg⁻¹ at a power density of 1145 W kg⁻¹ and outstanding cycling stability with ∼91% retention over 14 000 cycles. These experimental and theoretical insights highlight the strong potential of Zn–MnO₂/MoS₂ heterostructures for next-generation practical supercapacitor applications.