Reversible Li-storage in Titanium(III) Oxide Nanosheets

For the first time, the basic electrochemical properties and battery performances of titanium(III) oxide (Ti₂O₃) are reported in bulk and nanoscale powder forms in view of their potential applications for lithium ion battery electrodes. Ti₂O₃ reacts electrochemically with Li⁺ ions between 3.0 V and 0.01 V, and exhibits excellent cycling stability due to its relatively high electrical conductivity. Reactions between Li⁺ ions and Ti₂O₃ molecules are shown to proceed via intercalation of the former into the latter. To increase the electrochemical reactivity of Ti₂O₃, nanoscale Ti₂O₃ particles with and without graphene were prepared using a facile high-energy milling process. After milling, the specific discharge capacity of the nanoscale Ti₂O₃ with nanosheet morphology was 161 mA.h.g^-1 at the 300th cycle at a current density of 33 mA.g^-1. By combining graphene on the Ti₂O₃ nanosheets uniformly, the specific capacity was further improved to 248 mA.h.g^-1 at the 300th cycle. Furthermore, rate capability of these composite electrodes was enhanced significantly even at high current rates.