Novel LiNi1-xTix/2Mgx/2O2 compounds as cathode materials for safer lithium-ion batteries

A new class of LiNi1-xTix/2Mgx/2O2 materials has been synthesized. The comp ound LiNi0.75Ti0.125Mg0.125O2 showed a reversible capacity of 190 mAh/g and stable cycling was demonstrated. Differential scanning calorimetry studies showed much improved thermal stability of these materials in their totally charged states in contact with electrolyte. The exothermic peak at 220 deg rees C in a charged electrode containing LiNiO2 was drastically reduced as x increases in LiNi1-xTix/2Mgx/2O2. No exotherm was observed below 400 degr ees C for LiNi0.70Ti0.15Mg0.15O2 in its totally charged state. We believe t hat the use of these materials will improve the overall safety of Li-ion ba tteries. (C) 1998 The Electrochemical Society. S1099-0062(98)04-101-7. All rights reserved.