Li(1.33)Ti(1.6)7O(4) synthesized from Li2CO3 and TiO2 was electrochemically
inserted with lithium at room temperature. The defect spinel Li1.33Ti1.67O
4 and the fully lithiated Li2.33Ti1.67O4 with ordered rock-salt-type struct
ure show nearly identical X-ray diffractions. Due to similar lattice consta
nts of both phases and the low scattering factor of the lithium ions, the i
dentification of the insertion mechanism using X-ray powder diffraction is
possible only by using high angle X-ray scans of several samples inserted w
ith different amounts of Lithium. Precise analysis of the obtained data sup
plies the evidence for the presence of two distinct phases which are mutual
ly interconvertible upon lithium exchange. This result is in good agreement
with electrochemical data postulating a two-phase mechanism from the const
ant electrical potential found during cycling. (C) 1999 The Electrochemical
Society. S0013-4651(98)06-031-1. All rights reserved.