Preparation And Characterization Of Super Capacitor Material Containing Nb

Super capacitor is a new type of green energy storage element of a high power density and energy density, fast charging, long life, wide temperature range, safety and environmental friendliness, etc., having been successfully applied in many areas, and the application range is constantly increasing. Super-capacitor electrode material is the main factor affecting its energy-storing performance, leading to it a hot spot in some countries. Precious metal oxide RuO2 was first used in pseudo-capacitance material, from which the maximum ratio of capacitance values up to 720 F/g, yet it was limited for its high price. With the similar nature and ruthenium, abundant resources, and excellent electrochemical performance, niobium and manganese become a hot topic in recent years.In this paper, niobium ammonium oxalate and glucose were used as raw materials to prepare niobium-containing composite capacitance material by hydrothermal method in the foamed nickel substrate and niobium manganese composite capacitance material by hydrothermal electro-deposition method. Capacitance material prepared were characterized and compared concerning the electrochemical performance by SEM, XRD, combined with electrochemical performance testing under optimal conditions.Effects of molar ratio of the reactants of glucose and niobium ammonium oxalate, reaction time and reaction temperature on the amount of niobium oxide loaded on the nickel foam were researched. And the optimum conditions to prepare Nb composite capacitance material were determined combining with three factors and four levels orthogonal test: the molar ratio of the reactants of glucose and ammonium niobium oxalate 7:1, reaction temperature 200 ℃, reaction time 18 h. The prepared material containing Nb capacitor discharged current density of 0.5 A/g, the maximum specific capacitance reached 189.47 F/g, after 1000 cycles, the discharge specific capacitance retention rate remained above 95%, indicating it a promising super-capacitor material.By hydrothermal method and electro-deposition combination of manganese complexes prepared niobium investigated the influence electro-deposition process cycles and the scan rate of the composite ratio of manganese and niobium capacitors to determine the optimal electro-deposition conditions: CV scan rate 10 mV/s, 400 cycles. And the structure of the product, morphology and electrochemical properties were evaluated by FTIR, SEM, electrochemical workstation and blue electric test systems. The results showed that with current density increases, the specific capacitance of niobium and manganese composite electrode decreases. When the current density was 0.5 A/g, the specific capacitance reached 330.64 F/g, more than 1.5 times of a mere Nb-electrode. After 1000 cycles, the discharge specific capacitance retention rate remained above 93%, indicating it of a good electrochemical performance and cycle stability.