LixNi1-xO cathode structures were prepared by solid state reaction in air of nickel and lithium carbonate powder mixtures. Density changes of Ni/ Li2CO3composites following thermal treatment at 700°C were determined as a function of starting composition and isothermal time so as to evaluate the effect of Li2CO3content in the starting mixture on the microstructure of the resulting LixNi1-xO solid solutions. Total porosity, calculated from density data, increased up to the composition with 23 at% Li +, beyond which the porosity was nearly constant. An analysis of the compositions with nominal 30 and 44 at% Li + showed that, by Li2CO3decomposition during isothermal treatment at 700°C, both the amount and lithium atomic fraction of LixNi1-xO solid solution increased with time, but the porosity of the solid solution was unchanged. It was denoted that lithium carbonate affects lithium nickel oxide porosity by mass-to-void transformation during the reaction of Li2CO3with LiyNi1-yO to get LixNi1-xO with x > y, and by carbon oxide and/or carbon dioxide evolution following Li2CO3decomposition. While the specific pore volume related to mass-to-void transformation increased with Li2CO3amount, for high lithium content solid solutions, the specific pore volume, due to gas evolution, decreased with lithium carbonate content of the mixture. © 1997 Elsevier Science Limited and Techna S.r.l.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Process Chemistry and Technology
- Surfaces, Coatings and Films
- Materials Chemistry