Preparation And Electrochemical Peformance Of Mn-based Ternary Composite Electrode Materials

With the increasing environmental problems caused by traditional energy sources,green new energy has become a hot spot for research,so high energy efficiency and pollution free super capacitor arises at the historic moment,and became a widely used energy storage equipment.The properties of the electrode material play a decisive role on the performance of the super capacitor,so the electrode material research is the key of research,therefore,the development of high energy density,high discharge power,high rate performance,excellent cycle stability of the electrode material has become the direction of research.Based on manganese metal oxides.In this paper,manganese oxides(Mn O₂,Mn Co₂O_4.5)were set as the foundation,the transition metal oxide（Co₃O₄）,carbon materials（graphite）,conductive polymer（polypyrrole,polyaniline,）and metal organic framework（MOFs）of the ternary composite were prepared by a simple method and its electrochemical performance was studied,the specific contents are as follows:（1）The PPy/Graphene/MnO₂ ternary composites were synthesized by the method that combined the chemical oxidation polymerization in situ with the hydrothermal method using graphene oxide（GO）which was prepared by modified Hummers method as template,the morphology and structure of the composites were characterized by XRD,SEM,EDS,XPS and Raman,and the electrochemical properties such as capacity,rate performance and cycle stability were investigated by cyclic voltammetry（CV）,chronoamperometry（GCD）and AC impedance spectroscopy（EIS）.The results show that PPy/Graphene/MnO₂ composites have overcome the shortcomings such as the low cycle stability and Graphene capacity of PPy,as well as low and poor conductivity of MnO₂,showing a relatively large specific capacitance of 492.56 F·g-1 at 1 A·g-1 current density.（2）A novel ternary composite of Co₃O₄/PANI/MnO₂ with core-core-shell heterostructure was designed by a simple hydrothermal method and electrochemical deposition method.The morphology and structure of the composites were characterized by XRD,SEM,TEM,and the electrochemical properties were investigated by cyclic voltammetry（CV）,chronoamperometry（GCD）and AC impedance spectroscopy（EIS）.The results show that this heterogeneous structure of the composite material have the effect of individual synergy,at a high current density of 10 A·g-1,an ultra-high specific capacitance of 1686.7 F·g-1 was shown and a higher capacity retention of 114.9 % after 1000 cycles of charge and discharge,which has opened up the idea for the development of core-shell structure electrode material and provided the possibility for the construction of ideal supercapacitor,it provides a new idea for the development of the core-shell structure electrode material,and provided the possibility for the construction of ideal supercapacitor.（3）The Co₃O₄@Ni Co₂O₄@Mn Co₂O_4.5 ternary metal oxide composites with hollow polyhedral structure were synthesized by ion coprecipitation method using metal hexagonal framework ZIF-67 as template,the nanocomposites with special structure were characterized by XRD,SEM,EDS,TEM,XPS,FTIR and BET,and the electrochemical properties such as capacity,magnification and cycle stability were studied by cyclic voltammetry（CV）,chronoamperometry（GCD）and AC impedance spectroscopy（EIS）.The results show that the composite material still has a large capacity of 1060 F·g-1 at a high current density of 10 A·g-1,after 1000 cycles of charging and discharging,the capacity retention rate is as high as 98.1 % and the cycle stability is good,it is an ideal electrode material for supercapacitors.