Zhuobing Xiao

Synthesis and electrochemical properties of SnO2-CuO nanocomposite powders

Abstract SnO 2 -CuO nanocomposite powders were prepared by chemical coprecipitation method using SnCl 4 5H 2 O, NH 3 H 2 O and Cu(NO 3 ).3H 2 O as raw materials. The powders were characterized by thermogravimertric(TG) analysis and differential thermal analysis(DTA), X-ray diffraction(XRD), and scanning electron microscope(SEM). The electrochemical properties of SnO 2 -CuO and undoped SnO 2 powders as anode materials of lithium ion batteries were investigated comparatively by galvanostatic charge-discharge experiments and AC impedance. The results show that SnO 2 -CuO nanocomposite powders with the average particle size of 87 nm can be obtained by this method. The structure of SnO 2 does not change with the introduction of CuO, but the average particle size of nano-SnO 2 decreases. SnO 2 -CuO nanocomposite powders show a reversible capacity of 752 mA h/g and better cycleability compared with nano-SnO 2. The capacity retention rates after 60 cycles of nano-SnO 2 -CuO and SnO 2 are 93.6% and 92.0% at the charge-discharge rate of 0.1 C, respectively, which suggests that the introduction of CuO into SnO2 can improve the cycleability of nano-SnO 2.

Preparation and properties of Bi2Ti2O7 thin films by chemical solution deposition

Abstract Homogeneous and crack-free Bi 2 Ti 2 O 7 thin films with strong (111) orientation were successfully prepared on n-type Si (100) substrates by chemical solution deposition. Bismuth nitrate and titanium butoxide were used as starting materials. The crystallization temperature is relatively low and about 500°C.The insulating and dielectric properties were found to be dependent on the annealing temperature. The dielectric constant was 115.5 at 100 kHz at room temperature, and the leakage current density was 3.48 × 10 −7 A/cm 2 at an applied voltage of 15 V (375 kV/cm) for 0.4 μm-thick films annealed at 500°C for 30 min.

Thin-film lithium-ion battery derived from Li1.3Al0.3Ti1.7(PO4)3 sintered pellet

Abstract Thin-film lithium-ion battery of LiMn 2 O 4 Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 /LiMn 2 O 4 was fabricated using Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 sintered pellet as both substrate and electrolyte. Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 sintered pellet was prepared by sol-gel technique, and the thin-film battery was heat-treated by rapid thermal annealing. Phase identification, morphology and electrochemical properties of the components and thin-film battery were investigated by X-ray diffractometry, scanning electron microscopy, electrochemical impedance spectroscopy and galvanostatic charge-discharge experiments. The results show that Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 possesses a electrochemical window of 2.4 V and an ionic conductivity of 1.2 ×10 −4 S/cm. With Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 sintered pellet as both substrate and solid electrolyte, the fabricated thin-film battery with an open circuit voltage of 1.2V can be easily cycled.

The influence of crystallization route on the Bi4Ti3O12 thin films by chemical solution deposition technique

The thickness of the monolayer thin film made from chemical solution deposition (CSD) is often less than 0.1 μm, and in order to get thicker film, multiple coating is unavoidable. In our work, we found that different crystallization routes greatly influence the structural and electrical properties of the films. The leakage current density and dielectric constant of the films prepared by intermediate crystallized layer route are smaller than those of the films made from the intermediate amorphous layer route. The coercive field of the former is bigger than that of the latter, while the remanent polarization of the former is smaller than that of the latter.

Characterization of rapid thermally processed LiMn2O4 thin films derived from solution deposition

Abstract Cathode material LiMn 2 O 4 thin films were prepared through solution deposition followed by rapid thermal annealing. The phase identification and surface morphology were studied by X-ray diffraction and scanning electron microscopy. Electrical and electrochemical properties were examined by four-probe method, cyclic voltammetry and galvanostatic charge-discharge experiments. The results show that the film prepared by this method is homogeneous, dense and crack-free. As the annealing temperature and annealing time increase, the electronic resistivity decreases, while the capacity of the films increases generally. For the thin films annealed at different temperatures for 2 min, the thin film annealed at 800 °C has the best cycling behavior with the capacity loss of 0.021% per cycle. While for the thin films annealed at 750 °C for different times, the film annealed for 4 min possesses the best cycling performance with a capacity loss of 0.025% per cycle. For the lithium diffusion coefficient in LiMn 2 O 4 thin film, its magnitude order is 10 −11 cm 2 ·s −1 .