Reassembled Octatitanate/Carbon-Fiber Composites as High-Rate Lithium Insertion Electrode

Composites of octatitanate and carbon-fibers were prepared through reassembling tetratitanate nanosheets, synthesized through exfoliation / reassembly process, by the reaction with HCl in colloidal suspension mixed with carbon- fibers, followed by heat treatment. High-rate lithium intercalation properties were examined for the reassembled octatitanate / carbon-fiber composites, and compared with those of reassembled octatitanate simply mixed with carbon-particles. The reversible capacity and the energy efficiency of the reassembled octatitanate / carbon-fiber composites were 190 mAh/g and 94 %, respectively, larger than those of a conventional octatitanate or a reassembled octatitanate. Relatively large capacity of 135 mAh/g still remained at a large current density of 10 A/g, which corresponds to about 70 % of the discharge capacity at a relatively small current density of 100 mA/g. Reassembled octatitanate / carbon- fiber composites exhibited an excellent performance as a high-rate lithium insertion electrode.