Electrochemical Properties of Nanostructured Amorphous, Sol-gel-Synthesized TiO[sub 2]/Acetylene Black Composite Electrodes

Amorphous titanium oxide was prepared by a sol-gel route employing Ti(IV) alkoxide as a starting agent. The average size of the primary particles was about 4 nm, and the Brunauer-Emmett-Teller specific surface area was 390 m 2 g −1 . Addition of acetylene black in synthesis allowed us to obtain the composite of titania and carbon materials. The composite materials could be galvanostaticly discharged and charged around 2 V vs. Li / Li + . After thermal treatment at 330°C the composite showed specific capacity above 125 mA h g −1 , even under large discharge current of 10 A g −1 . Based on the relationship between specific capacity and current density, the chemical diffusion coefficient of lithium was estimated to be 6 × 10 − 12 cm 2 s − 1 .