MoO2 coated few layers of MoS2 and FeS2 nanoflower decorated S-doped graphene interoverlapped network for high-energy asymmetric supercapacitor

Ultra-thin layer MoS 2 coverd MoO 2 nanocrystal arraying on sulfur-doped graphene framework (MoS 2 -MoO 2 /3DSG) have been obtained via a simple hydrothermal procedure accompanied with high temperature annealing for hybrid supercapacitor applications. The asymmetric supercapacitor with MoS 2 -MoO 2 /3DSG as the positive electrode and FeS 2 /3DSG as the negative electrode can work efficiently and stably under the voltage of 0–1.7 V, and show super high energy density of 87.38 Wh kg −1 at the power density of 683.94 Wkg −1 . Herein, the ultra-thin layer MoS 2 coverd MoO 2 nanocrystal arraying on sulfur-doped graphene framework (MoS 2 -MoO 2 /3DSG) is obtained via a simple hydrothermal procedure accompanied with high temperature annealing. Sodium thiosulfate and ethanethiol are used as sulfur sources to form three-dimensional sulfur doped graphene (3DSG) in the hydrothermal process. Importantly, MoO 2 nano-particles are uniformly loaded on MoS 2 nanosheets and 3DSG via in-situ collaborative technology. As a result, the stable conductive network take full use of the characteristics of high specific capacitance of MoO 2 nanoparticles, convenient ion transport channel of two-dimensional MoS 2 nanoflakes and efficient charge transfer and cross-linked 3DSG to improve the electrochemical activity and enhance the dynamics of electrons / ions, which is up to 1150.37 F g −1 specific capacitance and maintains 94.6% of the original capacitance after 10,000 cycles. Also, FeS 2 nanoflowers in situ loading on 3DSG (FeS 2 /3DSG) with enhanced the overall performance of the device are fabricated. The asymmetric supercapacitor with the positive electrode of MoS 2 -MoO 2 /3DSG and the negative electrode of FeS 2 /3DSG can work efficiently and stably under the voltage of 1.7 V, and provide energy density of 87.38 Wh kg −1 at the power density of 683.94 Wkg −1 , displaying an outstanding application prospect for energy storage.