Electrochemical And Hydrothermal Deposition Synthesis Of Film Electrode Materials And Their Electrochemical Performance

In order to solve the urgent global problem in the wide use of fossil fuels and consequent lack of fuel and environmental pollution, the development of various energy storage and conversion systems has been the subject of recent attention. The advantages of high power density, high efficiency and long life expectancy have made electrochemical supercapacitors one of the major emerging devices for energy and power supply. Over the past ten years, the growth of electrode materials directly on conductive substrates as supercapacitors electrode has attracted more and more attentions because such a binder-free method can improve the electrochemical performance of supercapacitors. Compared with the traditional methods which required high energy consumption and long reaction time, the electrochemical and hydrothermal methods have low consumption, easy to control and clean. The investigation will be emphasised on the relationship between processing paramenters and electricapacior properties. The development of this project will offer a new idea and method to the improvement of electrochemical performance.This study includes the two aspects as follow. Herein, the growth of Ni-MOFs nanorods on Ni foam was developed by an effective and versatile electrosynthesis method. The effects of the reaction condition including reaction time, current density and temperature on the growth of the Ni-MOFs were investigated in detail and the structure and electrochemical properties of the Ni-MOFs materials were characterized. The results showed that the optimal current density and reaction time for the synthetic crystals is 7mA/cm2 and 10 h at the temperature 60 "CAs obtained Ni-MOFs composites deliver a specific electric capacitance of 25.63 F/g at a scan rate of 10mV/s and the capacities remained at 63.68%. Furthermore, the NiOx/C composites were obtained by carbonizing using Ni-MOFs as precursor. It exhibits an outstanding electrochemistry performance when the carbonization temperature is at 900℃, the highest specific capacitance of the carbonized sample is as high as 224.56 F/g at a scan rate of 10mV/s and the retained capacitance is at 92.83%.A facile hydrothermal synthesis has been developed for the preparation of FeS microsheetnetworks directly on Fe foil. The results showed on the influence of reactants, reaction temperature and time, and the source of S on the formation of FeS film. The as-prepared samples have the single phase FeS structure with high crystallinity at 200℃,36 h using H2NCSNH2 as sulfur source. The result of electrochemical properties showed that the specific capacitanceis 66.10 F/g when the scan rate is 10 mV/s, and 89.30%of its capacitance was retained for 1000 cycles. In addition, the another FeS crystallized samples were prepared using the C2H5NS as S source at 165℃,36 h by hydrothermal method, the FeS microsheet exhibits an specific capacitance of 65.83 F/g at the scan rate of 10 mV/s, and 87.20% of its capacitance was retained for 1000 cycles.