Electrochemical Exfoliated MoS₂ Nanosheets And Its Application Of Supercapacitor

As a dual-function green energy storage device,supercapacitors have some of the advantages of traditional capacitors and batteries,and have huge application value and potential in all areas of life.Studies have shown that two-dimensional（2D）molybdenum disulfide（MoS₂）nanomaterials have become one of the promising options for constructing excellent supercapacitors.However,the lack of a large-scale,efficient and low-cost method for preparing MoS₂nanosheets has severely hindered the practical application of MoS₂in the field of energy storage.The electrochemical exfoliating method is a newly developed effective way to prepare two-dimensional material nanosheets with high quality.It has the characteristics of simplicity,short cycle and considerable output.This paper takes MoS₂materials as the research object,explores the preparation of two-dimensional MoS₂nanosheets by electrochemical exfoliating method,and uses electrochemical technology to combine heterogeneous substances with it and prepare supercapacitors based on two-dimensional MoS₂and its composite materials as electrode materials.The main research contents are as follows:1.This article takes a typical 2D material—MoS₂as an example,and studies how to exfoliate bulk MoS₂into two-dimensional MoS₂nanosheets through a simple and inexpensive electrochemical cathodic exfoliating method,obtain nanomaterials with large specific surface area and rich edge sites.In a cheap and pollution-free inorganic salt solution,electrochemically exfoliating a large amount of MoS₂into high-quality MoS₂nanosheets with a size distribution range of 1-3μm and a thickness of a few nanometers is a facile and effective method.In addition,the MoS₂nanomaterials prepared by the electrochemical exfoliating method was constructed into electrodes and supercapacitors to explore its electrochemical performance.The 2D structure will provide a stable channel to promote the insertion/desorption of ions during the charging and discharging process,and can prevent deposition and aggregation to a certain extent.Therefore,compared with the unexfoliated MoS₂,the MoS₂nanosheets prepared in this way show a great improvement in the performance of the supercapacitor(for example,in a 0.5M KOH alkaline solution,the specific capacitance increases from the original 130 F g^-1To 215 F g^-1).This work provides basic research for the preparation of two-dimensional nanomaterials by electrochemical exfoliation.2.In order to design and prepare capacitor materials with high performance in a neutral environment.Here,the heterostructure of MnO₂nanoparticles supported on MoS₂nanosheets is synthesized in one step by means of electrochemical exfoliation.Through a series of characterization methods,it is fully confirmed that the electrochemical method not only efficiently prepares MoS₂nanosheets on a large scale,but also generates MnO₂simultaneously,thus constructing a MnO₂/MoS₂heterojunction.The results show that the MnO₂/MoS₂heterojunction has better electrochemical performance than MoS₂nanosheets.It has good capacitance even in neutral solution,and its specific capacitance at a current density of 2 A g^-1is 275 F g^-1.In addition,for the consideration of the evaluation of the cycle stability of the electrode,a long-term charge and discharge test was carried out,,and it showed a capacity retention rate of 90.5%,indicating that it has good stability.This work provides experimental basis and theoretical guidance for the large-scale preparation of two-dimensional nanomaterials and the realization of their functionalization.