Hydrothermal Preparation Of Molybdenum Disulfide Composites And Their Application In Supercapacitors

MoS₂,a kind of transition metal sulfide with layered structure,is used as electrode material for supercapacitors,which has higher intrinsic ionic conductivity than the metal oxides and higher theoretical specific capacitance than the graphite.In this work,different morphologies of MoS₂ were prepared by solvothermal method,and the effect of the morphology on the electrochemical properties was studied.In addition,CoS₂/MoS₂ and Ni₃S₄/MoS₂//CFP were synthesized to enhance the performance by synergistic effect in the composite materials.The main contents include the following aspects:?1?Different morphologies of MoS₂ were prepared by hydrothermal method with different molybdenum sources.The specific capacitance of hollow spherical MoS₂ and flowerlike MoS₂ are 196 F·g-1 and 116 F·g-1,respectively,at the current density of 1 A·g-1.The poor cycle stability of the pure MoS₂ limits the practical application as electrode material.Therefore,MoS₂ compounded with other materials to improve its electrochemical performance is another direction to enlarge its practical application used as electrode materials?2?A MoS₂/CoS₂ composite has been prepared successfully via an one-step hydrothermal method.Serving as a supercapacitor electrode,the obtained CoS₂/MoS₂ hybrid material exhibits a remarkable specific capacitance of 1038 F·g-1,a high rate capability of 71.7%,and excellent cycling stability of 84.76% retention after 10000 cycles.The superior electrochemical properties of the CoS₂/MoS₂ nanocomposite are attributed to the synergistic effects between the layered MoS₂ and the conductive CoS₂.The effect of molar ratio of molybdenum to cobalt on microstructure and electrochemical properties was further studied.When the molar ratio of molybdenum and cobalt is 2:1,the composites have the best structure and electrochemical performances.An all-solid-state asymmetric supercapacitor was successfully prepared using the CoS₂/MoS₂ as the positive electrode and the AC as the negative electrode.The CoS₂/MoS₂//AC asymmetric supercapacitor exhibits a high power density of 25.78 Wh·kg-1 and a high energy density of 793.2 W·kg-1,respectively.?3?Ni₃S₄/MoS₂ nanosheets grown on the carbon fiber paper?Ni₃S₄/MoS₂//CFP?were successfully prepared via a facile one-step hydrothermal technique.Serving as a supercapacitor electrode,the obtained Ni₃S₄/MoS₂//CFP exhibits a remarkable specific capacitance of 1296 F·g-1,high rate capability of 57.8%,and excellent cycling stability of 96.2% retention after 5000 cycles.The superior electrochemical properties of Ni₃S₄/MoS₂//CFP nanocomposite is attributed to the synergistic effects of the Ni₃S₄,MoS₂ and CFP.The as-prepared Ni₃S₄/MoS₂//CFP//AC has a high energy density of 12.8 Wh·kg-1 at a power density of 700 W·kg-1.