Preparation And Supercapacitors Properties Of Lead Dioxide

As intermediate energy storage systems between conventional capacitors and batteries, compared with the conventional battery, supercapacitors have high power density, long cycle life, no pollution and so on. With the rise of the new green electric vehicle and the development of various electronic communication technologies, the energy crisis and environmental protection are the core strategy of sustainable human development. Energy storage and conversion components for increasingly high demand, makes the development of supercapacitors raised to a new height. High-energy and power supercapacitors also demonstrated its unprecedented prospects application to the world. Recently, studies on supercapacitors are mainly become a hot spot.This dissertation carried out following the international foreland research, according to many literature materials. With activated carbon materials and lead dioxide as electrode materials for supercapacitors, through improved preparation methods of the materials and optimize electrode fabrication technology, developed the activated carbon electrode and the dioxide lead film electrode, and assembled it into the hybrid supercapacitor. By integrating various electrochemical and material methods, this dissertation has investigated the material preparation, electrolyte optimization, electrode preparation, capacitive property and mechanism of double-layer capacitance. The main results are as follows:1. Activated carbon has been used as electrode materials for supercapacitor, and assembled it into the double layer supercapacitor. By investigating the electrochemical performance of activated carbon electrode in 5.3 mol L-1 H2SO4(1.28 g cm-3),2 mol L-1 KC1 and 2 mol L-1 LiNO3 electrolyte, test the specific capacitance. Using constant current charge-discharge methods and electrochemical impedance spectrum measurement, research the double layer supercapacitor capacitance characteristics by using 5.3 mol L-1 H2SO4 electrolyte, the specific capacitance of 32.4 F g-1 at current density of 100 mA g-12. Use of graphite substrate as the anode current collector, lead oxide depositied on graphite by the galvanostatic method, and research the lead dioxide electrode morphology and structure features by SEM and XRD studies. And electrochemical performance of the hybrid supercapacitor investigated by using the lead dioxide electrode as positive electrode, the AC electrode as negative electrode and 5.3 mol L-1 H2SO4 as electrolyte were characterized by using constant current charge-discharge and EIS measurements. The results showed that the depositied current density had large effect on the electrochemical performance of the lead dioxide thin electrode, the lead dioxide electrode depositied using 25 mA cm-2 current density not only has high specific capacitance and good cycle stability. The hybrid supercapacitor assembled with lead dioxide prepared at current density of 25 mA cm-2 and an activated carbon delivered a specific capacitance of 128.4 F g-1 at current density of 150 mA g-1, and after 3700 cycles the specific capacitance remained 70%.3. Use of graphite as the anode current collector, lead oxide depositied on graphite by the cyclic voltammetric deposition method, and research the lead dioxide electrode morphology and structure features by SEM and XRD studies. And electrochemical performance of the hybrid supercapacitor investigated by using the lead dioxide electrode as positive electrode, the AC electrode as negative electrode and 5.3 mol L"1 H2SO4 as electrolyte were characterized by using constant current charge-discharge and EIS measurements. The results showed that the lead dioxide electrode depositied by cyclic voltammetric deposition method not only has high specific capacitance and good cycle stability. The hybrid supercapacitor assembled with lead dioxide and an activated carbon delivered a specific capacitance of 96.8F g-1 at current density of 500 mA g-1, and after 2000 cycles the specific capacitance remained 92%.