Preparation And Electrochemical Energy Storage Performance Of Several Novel Electrode Materials

Electrochemical energy storage devices have increasingly attracted more attention. The electrode materials are the most important factors which affect the capacity, power density and energy density of electrochemical energy storage devices. In this thesis, several novel composite electrode materials were successfully prepared with conductive polymers and graphene by using different raw materials and preparation methods. The performance of the composite electrode materials were studied in the field of electrochemical energy storage. The main contents are as follows:(1) Silicon/polyaniline/graphene composites were prepared by a simple in-situ polymerization and adsorption reduction method. The performance of silicon as the anode material of lithium battery was enhanced by using polyaniline as a coating layer, which could remiss the effect of volume expansion of silicon, meanwhile, graphene could further reduce the resistance of the material. The capacity of the ternary composite reached 795.3 mAh g-1 when charged and discharged for 50 cycles at the current density of 0.2 A g-1. The results indicate that polyaniline and graphene can enhance the electrochemical performance of silicon materials.(2) A ternary composite was prepared with graphene, polypyrrole and lithium manganate which was used as a traditional electrode material in lithium ion batteries. The electrochemical performance of the composite was investigated in lithium sulfate electrolyte. The specific capacitance of the composite could reach 208 F g-1, far exceeding from lithium manganate and several other binary composite materials. It is a development of the application of traditional materials for lithium ion batteries in the field of supercapacitors.(3) Nitrogen doped graphene/nickel ferrite/polyaniline ternary composite material (NGNP) and nitrogen doped graphene material (NGE) were prepared by hydrothermal method and in situ polymerization. A lithium ion hybrid capacitor was assembled with the ternary composite as an anode and NGE as a cathode. The energy density of the hybrid capacitor was 53.9 Wh kg-1 when its power density was 670 W kg-1, while the energy density was 29.3 Wh kg-1 as the power density was 6350 W kg-1. The hybrid capacitor shows the potential application as a new energy storage in the future due to the high energy density and power density.