Lithium nickelate electrodes with enhanced high-temperature performance and thermal stability

Lithium nickelate is an attractive positive electrode material for lithium ion batteries because of its large capacity at ambient temperatures. However, highly delithiated LiNiO(2) (e.g. Li(0.2)NiO(2)) shows undesirable exothermal heat at 200 degrees C. We found another issue of LiNiO(2) in this study, namely poor reversibility at 40 degrees C. To overcome the-se disadvantages, we introduced cobalt, manganese, and titanium as partial substituents for nickel. Cobalt substitution was effective in improving the reversibility at 40 degrees C. The exothermal decomposition of the delithiated compounds was suppressed by using manganese and titanium as substituents. We found doubly substituted nickelate LiNi(0.8)Co(0.1)Ti(0.1)O(2) to be the most promising in terms of large capacity (190 mA h g(-1)), enhanced high-temperature performance, and improved thermal stability. (C) 2000 Elsevier Science S.A. All rights reserved.