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

Herein, the ultra-thin layer MoS2 coverd MoO2 nanocrystal arraying on sulfur-doped graphene framework (MoS2-MoO2/3DSG) 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, MoO2 nanoparticles are uniformly loaded on MoS2 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 MoO2 nanoparticles, convenient ion transport channel of two-dimensional MoS2 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, FeS2 nanoflowers in situ loading on 3DSG (FeS2/3DSG) with enhanced the overall performance of the device are fabricated. The asymmetric supercapacitor with the positive electrode of MoS2-MoO2/3DSG and the negative electrode of FeS2/3DSG 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. (C) 2020 Elsevier Inc. All rights reserved.

Automated summary

A MoS2-MoO2/3DSG supercapacitor with high specific capacitance and excellent cycle stability, together with a FeS2/3DSG supercapacitor with high energy density, were fabricated in this study. The asymmetric supercapacitor composed of positive and negative electrodes showed outstanding application prospects.