The Preparation And Modification Of Straw Based Activated Carbon And Application To Supercapcitors

The straw had natural plant fiber structure, so it was chose as carbon source. The activated carbon for electrochemical double layer capacitors (EDLCs) was prepared from straw by carbonization and subsequent activation.The morphologies of the as-prepared activated carbon were observed by scanning electron microscope (SEM). The specific surface area and pore structure were determined by nitrogen adsorption isotherms at 77K. And the capacitance performances were determined by cyclic voltammetry (CV), Chronopotentiometry, AC impedance (EIS). Then, the effect of raw material species, carbonized conditions, activated conditions, activated methods and temperature controlling ways was researched. The capacitance performances in different electrolytes were determined. And the influences of electrode mixture ratio and fabricating process on the results were analyzed. Based on the pore structures and capacitance performances of activated carbons, the relation between structure and performance of electrode material was discussed by experimental data analysis and thermal gravimetric analysis (TGA) of AN impregnated carbon.The results revealed the as-prepared activated carbon had the honeycomb-like morphology, large specific surface area and excellent capacitance performance. The preparing process had an important effect on the performance of the as-prepared activated carbon. The activated carbon prepared at high temperature was apt to electrode material of EDLCs in organic electrolytes, however it prepared at low temperature was apt to that in inorganic electrolytes. The specific capacitance exceeded 400 F/g in inorganic electrolyte, and it reached 251.1 F/g in organic electrolyte.Based on the researches of nickel oxide capacitance performances, nickel oxide and other transition metal compounds/activated carbon composite electrode materials were prepared and researched. On the one hand, the activated carbon was modified in the activated process by adding metal compounds, and on the other hand, it was modified by soakage. The capacitance performances of composite electrode materials were researched. The results indicated that their usable potential range became wide.The researches on charge-discharge test and remote monitoring system were carried out. Based on LabVIEW, the multi-channel system was fabricated using Advantech PCI-1710HG multifunctional data acquisition card. The charge-discharge test and remote monitoring system were established and applied to EDLC charge-discharge test. After modification of the system, it applied to many experiments, such as electrolyte conductance measurements, freezing point measurements. The results showed that the system had friendly operation panel, and it not only had the advantages of multi-channel and quick acquisition, but also was easy to be maintained and added, and it could carry out remote monitoring of experiments.