Controllable Preparation Of Molybdenum Disulfide Nanosheets And Their Supercapacitor Performances

Supercapacitors are a class of advanced electrochemical storage energy devices.It has a long service life,fast charging and discharging rate,higher energy density,high power density and large specific capacitance.Therefore,it is regarded as One of the most promising energy storage devices in the future.MoS₂ nanosheets have a two-dimensional layered structure of graphene-like and are a potential supercapacitor electrode material.MoS₂ nanosheets tend to aggregate together in solution,resulting in a decrease in the effective specific surface area of the material and a decrease in performance.2H-MoS₂?Semiconductor phase?and 1T-MoS₂?Metal phase?are two common forms of crystal structure of MoS₂,in which 1T-MoS₂ nanosheets have excellent hydrophilic surface and electrical conductivity,and 2H-MoS₂ nanosheets are more stable.Preparation of excellent performance and structurally stable MoS₂nanosheets is a prerequisite for supercapacitor applications.The purpose of this paper is to control the preparation of MoS₂ nanosheets.The electrochemical properties of the two composites were investigated by hydrothermal method on the surface of titanium dioxide nanotube arrays by preparing 1T-MoS₂?1T-MoS₂@TiO₂/Ti?and using graphene oxide nanosheets as template to grow 2H-MoS₂?2H-MoS₂@RGO?.The research contents are as follows:?1?“Limited”growth of 1T-MoS₂ nanosheets in titanium dioxide nanotube arrays.A titanium dioxide nanotube array was prepared by electrochemical anodization.The1T-MoS₂@TiO₂/Ti nanocomposite was obtained by“limited”growth of 1T-MoS₂nanosheets between titanium dioxide nanotube arrays?TiO₂/Ti?using a simple hydrothermal method.The morphology and structure of 1T-MoS₂@TiO₂/Ti were characterized by FESEM,TEM,EDX,XRD,XPS,Ramam and contact angle,and the formation mechanism of the morphology was investigated.The 1T-MoS₂@TiO₂/Ti electrode provides a specific capacitance of 429 F g^-1 at a current density of 0.2 A g^-1and excellent cycle stability?capacitance retention of approximately 97%after 10,000cycles?.When the current density is 0.2 A g^-1,the energy density of the 1T-MoS₂@TiO₂/Ti electrode can reach 48.2 Wh kg^-1.?2?The controllable preparation of 2H-MoS₂ nanosheets is realized by using GO as a template.Graphene oxide?GO?was prepared by modified Hummers method,and MoS₂ nanosheets were prepared by simple hydrothermal method using GO as template to obtain 2H-MoS₂@RGO nanocomposites.The morphology and structure of 2H-MoS₂@RGO were characterized by FESEM,XRD and XPS techniques,and the mechanism of morphology formation was studied.The 2H-MoS₂@RGO electrode provides an area specific capacitance of up to 2148 mF cm^-2 at a current density of 0.5mA cm^-2 and a capacitance retention of approximately 93%after 5000 cycles,exhibiting excellent capacitance performance,cycle stability and rate performance.In this paper,the simple hydrothermal method can be used to control the 2H-MoS₂@RGO and 1T-MoS₂@TiO₂/Ti electrode materials,improve the electron conductivity and hydrophilicity of the electrode material,and solves the agglomeration phenomenon of the two-dimensional layered material.These performance optimizations further accelerate the transfer rate of ions and electrons in the electrodes and electrolytes,thereby improving the electrochemical performance of the electrodes.This controllable method of preparing materials provides a novel idea for us to design electrode materials to improve electrochemical performance in the future.