Ben-Lin He

Lithium Insertion into TiO2 Nanotube Prepared by the Hydrothermal Process

A TiO 2 nanotube was prepared by a hydrothermal process. Transmission electron microscope tests showed that the products are uniform straight hollow tubes with the diam around 8 nm and the length over 300 nm. X-ray diffraction measurements indicate that the nanotubes crystallized in anatase TiO 2 . Cyclic voltammetry and galvanostatic charging and discharging tests showed that lithium-ion intercalation/deintercalation occured reversibly in the TiO 2 nanotube electrode, and a high capacity can be obtained. Electrochemical impedance spectra show that Li + ion intercalation occurs below 2.2 V. Around the 1.7 V plateau, the total electrochemical resistance reached a minimum.

Preparation and Electrochemistry of SWNT/PANI Composite Films for Electrochemical Capacitors

Single-walled carbon nanotube/polyaniline (SWNT/PANI) composite films were prepared by in situ electrochemical polymerization of an aniline solution containing different SWNT contents. Surface morphology and structural properties of these PANI-based films were examined by a scanning electron microscope and X-ray photoelectron spectroscopy. The electrochemical capacitance properties of these films were investigated with cyclic voltammetry, charge-discharge tests, and ac impedance spectroscopy. The composite film, based on the charge-transfer complex between well-dispersed SWNT and PANI matrixes, shows much higher specific capacitance, better power characteristics, and is more promising for applications in capacitors than a pure PANI film electrode.

One-Step, Low-Temperature Route for the Preparation of Spinel LiMn2O4 as a Cathode Material for Rechargeable Lithium Batteries

A new low-temperature synthetic route has been developed and demonstrated for the production of spinel LiMn 2 O 4 as a cathode material for Li-ion batteries. The process involves the insertion of lithium into electrolytic manganese dioxide with glucose as a mild reductant in an autoclave. The material resulting from hydrothermal treatment is a spinel-structured Li 0 . 9 2 LiMn 2 O 4 with reasonable crystallinity. It exhibits promising electrochemical behavior in nonaqueous liquid electrolyte. The influence of hydrothermal temperature and the effect of glucose in determining the final structural integrity and electrochemical performance have also been systemically explored. Furthermore, the capacity degradation of low-temperature synthesized spinels was studied by cyclic voltammetry and X-ray diffraction. This capacity fading can be mainly attributed to the factors of structural degradation and loss of active materials.