Publication Date:
2012-04-15
Description:
This study examined the formation mechanism of Li 4 Ti 5 O 12 by a solid-state reaction between Li 2 CO 3 and TiO 2 for applications in lithium ion batteries. To explain the intermittent existence of rutile TiO 2 in the final Li 4 Ti 5 O 12 , five types of TiO 2 which had different anatase/rutile ratios were used as starting materials. Anatase to rutile-phase transformation occurred from 600°C, which is significantly lower than the typical TiO 2 transition temperature, when a pure anatase TiO 2 and Li 2 CO 3 mixture were heat-treated. Moreover, this rutile TiO 2 transformed from pure anatase TiO 2 was found to be more rigid in the solid-state reaction than an intact rutile or anatase-rutile mixture, existing in the final Li 4 Ti 5 O 12 , even after heat treatment at 900°C for 15 h. This difference is explained by the anatase/rutile-phase boundaries where an amorphous Li -precursor was located, enhancing the solid-state reaction due to the decreased diffusion path. Based on the observations, different formation mechanisms of Li 4 Ti 5 O 12 depending on the types of TiO 2 starting materials were proposed.
Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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