Electrochemical properties of nanostructured amorphous, sol-gel-synthesized TiO2/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 330degreesC 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 x 10(-12) cm(2) s(-1). (C) 2004 The Electrochemical Society.