Electrostatic self-assembly of MoS₂/graphene hybrid films for energy storage in high-performance symmetric supercapacitor

A fabrication strategy involving the electrostatic self-assembly of positively charged molybdenum disulfide (MoS₂) nanosheets and negatively charged graphene oxide (GO) sheets and thermal reduction process is proposed to prepare MoS₂/graphene hybrid films. The incorporation of MoS₂ nanosheets embedded in graphene sheets serves as spacers, preventing the graphene sheets from restacking. The optimized free-standing MoS₂/graphene hybrid film (MoS₂/G-2) demonstrates a remarkable areal specific capacitance of 979 mF cm⁻² at 1 mA cm⁻², which is 2.85 times as much as pure reduced graphene oxide (rGO) (343 mF cm⁻²). Benefiting from the layer-layer self-assembly structure and good synergistic effect, MoS₂/G-2 electrode exhibits enhanced capacitive performance with excellent cycling stability and no capacitance attenuation after 3000 cycles. Furthermore, by utilizing MoS₂/G-2 as electrode material for the assembled symmetric supercapacitors (MoS₂/G-2//MoS₂/G-2), a superior areal energy density of 20 μWh cm⁻² at the areal power density of 600 μW cm⁻² is achieved. The prepared hybrid film materials hold immense potential in constructing high-performance film electrode for electrochemical energy storage.