Synthesis and lithium insertion properties of ramsdellite LixTiO2 anode materials

Abstract

Ramsdellite LixTiO2 (x=0.47) with reduced form is successfully prepared as a single phase by heating an amorphous lithium peroxo-polytitanate in 4.8% H2 at 1100°C for 0–1h. The XRD data are well refined with the space group Pnma with a=0.96076nm, b=0.29514nm and c=0.50276nm. The ramsdellite LixTiO2 transforms into a rutile–ramsdellite intergrowth phase by extending the heating time to 1.25–4h. The capacity of the ramsdellite LixTiO2 in the region of 1.0–2.5V (vs Li) is 208mAhg−1 at 0.8C rate (0.13mAmg−1), substantially larger than that of the ramsdellite Li2Ti3O7 with oxidized form. The lithium insertion and deinsertion proceeds in two stages: a sloping region at higher potential (1.4–2.3V) and a plateau region at lower potential (1.3–1.4V).