Hui Zhan

Low-temperature sol–gel synthesis of Li1.2V3O8 from V2O5 gel

A new low-temperature synthesis route of Li1.2V3O8 for use as cathode active material in lithium secondary batteries from V2O5 gel is proposed. Reacting V2O5 gel with stoichiometrical LiOH·H2O under mild stirring forms Li1.2V3O8 gel. By heating Li1.2V3O8 gel at various temperatures in air, Li1.2V3O8 with different degrees of crystallinity have been obtained. TEM, TG–DTA and XRD experiments were carried out for physical characterization and the galvanostatic charge–discharge experiments for checking their electrochemical performance. The low-temperature sol–gel products have lower crystallinity and higher specific capacity than those synthesized by high temperature solid-state method.

Synthesis and electrochemical properties of polypyrrole-coated poly(2,5-dimercapto-1,3,4-thiadiazole)

Abstract A new composite cathode active material, conductive polypyrrole (PPy)-coated poly(2,5-dimercapto-1,3,4-thiadiazole) (PDMcT) was prepared as a thin film via the surfactant template (TFST) technique. The formation of the uniform and well-connected film on the surface of PDMcT particles was confirmed by Fourier transform infrared spectra (FT-IR) and transmission electron micrographs (TEM). By cyclic voltammetry and galvanostatic charge–discharge tests, the coated composite showed a better electrochemical performance than PDMcT, such as enhanced redox processes and improved coulumbic efficiency, etc. The electrical conductivity of the material reached to 10 −3 S cm −1 and an initial discharge capacity of 250 mAhg −1 was obtained. Moreover, it showed a slower fading of discharge capacity than PDMcT when used as cathode material in secondary lithium batteries with liquid electrolyte solution.

Facile preparation of Ag2V4O11 nanoparticles via low-temperature molten salt synthesis method

Nanosized Ag2V4O11 powders have been prepared via the low-temperature molten salt method using LiNO3 as a reaction medium. The powders have been characterized by x-ray diffraction and transmission electron microscopy. The discharge properties of the powders have been assessed by the galvanostatic discharge test using CR2016 coin cells. The powder made at 300°C for 2 h is composed of nearly spherical particles about 40 nm in size. The discharge test shows that the powders prepared by the low-temperature molten salt method exhibit high discharge capacities.

Influence of Acetylene Black Colloidal Solution on the Reactivation of the Simulation and Deactivation PbO2/PbSO4 Electrode

To investigate the influence of a kind of acetylene black colloidal solution (ABCs) on the regeneration of inactivation PbO2/PbSO4 electrode, the simulation deactivation PbO2/PbSO4 electrode was prepared by which PbCO3 acted with H2SO4 to produce PbSO4 and PbSO4 was in situ electro-oxidized to PbO2. The cyclic voltammetry and scanning electron microscope had been used to test the electrochemical performance and observe surface topography respectively. The experimental results show that the electrical conductivity of PbSO4 and PbO2 particles may be enhanced because of the adsorption of ABC particles on PbSO4/H2SO4 and PbO2/H2SO4 interface. Its adsorption behaviors can control the size of PbSO4 particles. In the process of the anode reactivation, PbO2/PbSO4 electrode process polarization can be reduced. The electrode REDOX current and capacity are improved in H2SO4 with ABCs. ABC colloidal particles can be conducive to the structure improvement of the simulation deactivation PbO2/PbSO4 electrode. Its electrochemical performance can be reactivated.