Effect of silver addition on the properties of combustion synthesized nanocrystalline LiCoO2

Nanocrystalline (similar to 50 nm) LiCoO2 powders containing 0-10 mol% of Ag have been prepared by combustion synthesis using citrate-nitrate combustion route. Thermal analyses show a sharp decomposition of the gel at similar to 177 degrees C for pristine LiCoO2. With addition of silver, the decomposition becomes sluggish and it completes only above 430 degrees C. X-ray powder diffraction analyses show an increase in lattice parameter, c, with increasing Ag content suggesting the occupation of Ag within LiCoO2 interlayer spacings. Transmission electron microscopy indicates diffusion of Ag into LiCoO2 grains. It has been observed that adding 1.0 mol% silver increases the room temperature electrical conductivity by more than two orders of magnitude (1.5 x 10(-3) S cm(-1)). Galvanostatic charge-discharge profiles of coin cells fabricated with the synthesized powders show a two-fold enhancement in the discharge capacity for 1.0 mol% Ag-added LiCoO2 cathode (140 mAh g(-1)) compared to that for pristine LiCoO2 (70 mAh g(-1)). (C) 2008 Elsevier B.V. All rights reserved