Wei Niu

Study on Negative Graphite Felt Electrode in the Lead Acid Flow Battery

This paper described the liquid flow battery system with graphite felt electrode and a single electrolyte, lead(II)in methanesulfonic acid. The kinetics behavior, cyclic voltammetry behavior and effects of treatment methods on kinetics behavior of Pb(II)/Pb couple were studied. The results show that the equilibrium electrode potential Pb(II)/Pb couple was -0.228V and the Pb(II)/Pb couple on graphite felt electrode had a good kinetics behavior. The cyclic voltammetry behavior of Pb(II)/Pb couple on graphite felt electrode was studied, and the oxidization and reduction peak potentials were -0.055V and -0.44V, respectively. The graphite felt treated with sulfuric acid had little oxidization and reduction peak potentials difference, and showed good electro-catalytic activity for Pb(II)/Pb couple.

Flame-Fusion Growth of Rutile Single Crystal

Single crystal of Rutile has been grown successfully by the flame fusion method by using high purity (4N5) ultrafine titania powder as starting material. The effects of growth atmosphere, growth rate and temperature gradient in the chamber on crystal growing were investigated and the specific growth conditions have been defined. The annealing of the as-grown crystals was performed in the oxygen and in the air respectively. It was shown that growth atmosphere where the oxygen partial pressure is higher than that of the oxygen decomposing pressure at the liquid-solid interface is a necessary condition for growing perfect crystals. In addition to reducing thermal stresses, the more important role of annealing is to eliminate oxygen vacancies by oxidization reaction. The annealing time can be considerably shortened in an oxygen atmosphere as compared to in the air and the grown crystal has more perfect structure.

Current Distribution on the Electrode in 3-D Networks Lead-Acid Batteries

The current distribution on the grid and plate in lead-acid batteries was determined mathematically by using the equivalent circuit method. The grids used in lead-acid batteries are the general lead grids and the 3-D networks grids, respectively. The calculated current distribution on the grid and plate of three-dimension networks lead-acid battery is more uniform than that of general lead-acid battery. To make the current distribution nearly uniform, extended current tabs located between two plate electrodes were proposed, and a sandwich networks plate was formed.

Study on the Key Technology of High Purity Strontium Titanate Powder Synthesized from Oxalic Acid Co-sediment Precipitation

Oxalate coprecipitation is applied in this paper, high purity titanium tetrachloride, and after the purification of strontium chloride, match with a certain concentration of solution, oxalate and strontium chloride and titanium tetrachloride in 1.005:1.000 make strontium titanium mixture ratio, slowly under 60°C to join in oxalic acid solution, aging around 4 h, get oxygen titanium strontium oxalate (SrTiO(C2O4)2 • 4H2 ) precipitation, after washing, drying and other process made oxygen titanium strontium oxalate powder.

Combustion Characteristic in Growth Chamber for Preparation of Single Crystal with Hydro-Oxygen Flame Fusion Method

Combustion characteristic in growth chamber for preparation of single crystal with hydrooxygen flame fusion method was investigated. The results show that along the centerline of growth chamber a peak temperature 3504.3 K could be reached when the flow rates of oxygen and hydrogen were 6 L/min and 20 L/min respectively. With the increasing hydrogen flow rate, the temperature of the center and the diameter of the central flame increased gradually in the chamber. With the increasing oxygen flow rate, the position of the peak temperature gradually moved down, which downward moved 5 mm when the central oxygen flow rate increased for 1 L/min, while the average temperature rose ca 230℃at a distance 110 mm to the nozzle. The diameter of hydrogen distribution circle had little effect on the center and radial temperature distributions, the central oxygen impact and the ignition position of the flame. As a result, the optimal position for single crystal growth could be easily acquired for the preset flow rates of the two gases and vice versa.

Study on Kinetics Behavior of PbO2/Pb(II) Couple in Graphite Felt Electrode

This paper described the liquid flow battery system with graphite felt electrode and a single electrolyte, lead(II)in methanesulfonic acid. The kinetics and cyclic voltammetry behavior effects of PbO2/Pb(II) couple were studied. The results show that the equilibrium electrode potential PbO2/Pb(II) couple with good kinetics behavior was 1.21V. The cyclic voltammetry behavior of PbO2/Pb(II) couple on graphite felt electrode was studied, and the oxidization and reduction peak potentials were 1.547V and 1.241V, respectively. The graphite felt treated with sulfuric acid showed good electro-catalytic activity for PbO2/Pb(II) couple.

Study on Kinetics Behavior of the Lead Negative Electrode in the Lead Acid Flow Battery

The chemistry system with negative graphite felt electrode and a single electrolyte, lead(II)in methanesulfonic acid, was described. The effects of treatment methods on kinetics and cyclic voltammetry behavior of Pb(II)/Pb couple were studied. The results show that the equilibrium electrode potential Pb(II)/Pb couple was -0.233V and the Pb(II)/Pb couple on graphite felt electrode had a good kinetics behavior. The cyclic voltammogram of graphite felt electrode showed that the oxidization and reduction peak potentials were -0.044V and -0.454V, respectively. The graphite felt treated with methanesulfonic acid had little oxidization and reduction peak potentials difference, and showed good electro-catalytic activity for Pb(II)/Pb couple.