Novel Layered Li-Cr-Ti-O Cathode Materials Related to the LiCrO[sub 2]-Li[sub 2]TiO[sub 3] Solid Solution

Abstract

The electrochemical properties of novel layered Li-Cr-Ti-O cathode materials related to the LiCrO2­Li2TiO3LiCrO2­Li2TiO3 solid solution were described. These materials demonstrated that Cr3+/Cr6+Cr3+/Cr6+ is capable of reversibly cycling in a Li2TiO3Li2TiO3 -like framework. The sample with y=0.5y=0.5 (the content of Ti/(Ti+Cr)Ti/(Ti+Cr) at starting compositions) was found to be the most promising cathode material in light of the high capacity and excellent cycling performance. It can deliver the discharge capacities of 202 and 173 mAh/g at 60°C and 30°C, respectively. Further characterizations on the sample, including chemical analysis, scanning electron microscopy, rate charge/discharge, quasi-open-circuit voltage, cyclic voltammetry, and ex situ X-ray diffraction and constant-capacity charge/discharge tests were performed. The results showed that this material has a relatively slow kinetics of Li+Li+ diffusion and the original layered structure gradually changes to a disorder structure during cycling; furthermore, during the process two distinct phases with similar structure were observed. © 2003 The Electrochemical Society. All rights reserved.