Preparation And Electrochemical Properties Of Composite Electrodes Based On Polyaniline/nano Functional Materials

Supercapacitors have attracted extensive attention due to the fast charge-discharge speed,high power density,good cycle stability et al.Since the electrochemical performance largely depends on the properties of electrode materials,the development of efficient electrode materials is extremely important for promoting the application of supercapacitors.Among the various electrode materials,polyaniline（PANI）is considered to be a promising one due to the good electrochemical activity,high theoretical specific capacitance,and facile preparation.However,the poor rate capability and cycling stability of PANI significantly limit its wide application.An effective approach is to add nanomaterials with excellent electrical conductivity and stability,such as graphene,carbon nanotubes（CNTs）,transition metal sulfides,etc.,to enhance the electrochemical performance through the synergistic effect of multiple components.In this paper,Mo S2 were prepared by solid-phase ball milling and hydrothermal methods,respectively,and were complexed with PANI and CNTs to provide binary or ternary composite electrode materials.The morphology and electrochemical properties of the composites were characterized,and the effects of each component on the properties of the electrode materials were investigated.The main research contents including follows:Part 1:Preparation and electrochemical properties of PANI/Mo S2-LS binary composite electrode material.Lignosulfonate（LS）modified Mo S2 nanosheets（Mo S2-LS）were prepared by solid-phase ball milling using calcium lignosulfonate as exfoliant.The Mo S2-LS was used as template for the in-situ polymerization of aniline,which resulted in PANI/Mo S2-LS binary composite material.The effect of Mo S2-LS on the morphology and electrochemical performance of PANI was studied.It was found that after the addition of Mo S2-LS,PANI grew more regularly on the surface of Mo S2 nanosheets to form a relatively flat structure.The PANI/Mo S2-LS binary composite electrode material exhibited a high specific capacitance of 393.6 F g^-1 at a current density of 1 A g^-1 in 1.0 M H2SO4 in a three-electrode system,which is 1.4 times higher than that without adding Mo S2 nanosheets.Part 2:Preparation and electrochemical properties of PANI/Mo S2-LS/CNT-LS ternary composite.To further improve the electrochemical performance of the above binary composite electrode materials,LS functionalized carbon nanotubes（CNT-LS）we introduced to PANI/Mo S2-LS to give a ternary composite material PANI/Mo S2-LS/CNT-LS.Effect of CNT-LS on the morphology and electrochemical properties of the composite material was investigated.The results showed that the addition of CNT-LS is beneficial to the formation of porous structures,thus provides more active sites for redox reactions.The PANI/Mo S2-LS/CNT-LS ternary composite exhibited a high specific capacitance of 458.9 F g^-1 at 1 A g^-1 in 1.0 M H2SO4 in a three-electrode system.A capacitance retention rate of 86.0%was obtained after 10,000 charge and discharge cycles,showing excellent cycle stability.The specific capacitance and capacitance retention were increased by nearly 1.2 times and more than 1.3 times than those without CNT-LS,respectively.Part 3:To study the effect of Mo S2 morphologies on the electrochemical performance of the related electrode materials,CNT-LS was used as a template to prepare petal-shaped Mo S2 nanospheres through hydrothermal method.The resultant binary composite Mo S2@CNT-LS was used as a template for in-situ polymerize of aniline,which provided the ternary composite PANI/Mo S2@CNT-LS.It was found that the Mo S2 nanospheres,having a hierarchical structure,can provide more active sites.The growth of PANI on the Mo S2@CNT-LS surface can reduce the aggregation of Mo S2,which is beneficial to the improvement of electrochemical performance.The PANI/Mo S2-@CNT-LS ternary electrode material showed a specific capacitance of 433.0 F g^-1 at 1 A g^-1 in 1.0 M H2SO4 in a three-electrode system,which is slightly lower than that of the composite electrode based on Mo S2 nanosheets（in the second part）.However,the cycle stability was slightly enhanced,that is,the capacitance retention rate is 95%after 10,000 charge and discharge cycles.These results indicates that both Mo S2 nanosheets and nanospheres can effectively improve the electrochemical performance of PANI,and can be used for the construction of efficient composite electrodes.