Chromium oxides and lithiated chromium oxides. Promising cathode materialsfor secondary lithium batteries

Chromium oxides and lithiated chromium oxides were synthesized by thermal d ecomposition of chromium trioxide (CrO3) at high temperatures and oxygen pr essures. Synthesis temperature and pressure markedly affect the performance of these cathode materials. Higher pressures lead to a higher O/Cr ratio a nd fewer impurities in the final product. These materials are stable interc alation hosts for lithium, and exhibit a higher capacity than any of the pr ominent positive electrodes used in secondary lithium batteries. m-CrOx has a capacity of 255 mAh/g, while m-LiCrOx has a capacity of 210 mAh/g, durin g the first discharge. The average voltage of these cells is 3.0 V vs. Li/L i+ that gives an average energy density of approximately 650 Wh/Kg. (C) 199 8 The Electrochemical Society. S1099-0062(98)07-090-4. All rights reserved.