Reversible Li-storage in Titanium(III) Oxide Nanosheets

• New anode, Ti2O3 reacts with Li+ ions between 0 and 3 V and has an excellent cycling stability.
• Nanosheet-shaped nanoscale Ti2O3 were synthesized using a bead-milling process.
• More than 0.86 Li+ ion are inserted per nanosheet-Ti2O3 group after 300th cycle.
• Graphene-wrapped nanoscale Ti2O3 exhibits the best battery performances.

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.

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