Electrochemical Properties of Sol-Gel Prepared Li2ZrxTi1-x(PO4)(3) Electrodes for Lithium Secondary Batteries

LiZr2-xTix(PO4)(3) with x 0, 0.5, and 1.0 were synthesized by a sol-gel method and electrochemically cycled as an anode for Li-ion batteries. LiZr2-xTix(PO4)(3) with rhombohedral structure (space group, R (3) over barc) underwent irreversible amorphization during the first Li insertion, leading to a large loss of the discharge capacity. The resulting amorphous phase, however, well maintained their discharge capacity (60.4 mAh g(-1), 74.6 mAh g(-1), and 149.6 mAh g(-1) for LiZr2(PO4)(3), LiZr1.5Ti0.5(PO4)(3), and LiZrTi(PO4)(3), respectively, cycled 0.2 mA cm(-2) between 0.1 and 3 V) during an extended electrochemical cycling. It was shown that the Ti addition substantially increased the discharge capacity of LiZr2(PO4)(3), although the addition caused gradual capacity fading during cycling when added in excess. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3551533]