THIN-FILM CATHODES FOR SECONDARY LITHIUM BATTERIES

We have prepared thin films of the active cathode materials LiCoO2 and LiMn2O4 by chemical techniques. Low pressure chemical vapor deposition was successful at readily preparing LiCoO2 at temperatures ranging from 450 to 650 degrees C; however, in order to prepare the spinel phase LiMn2O4 temperatures greater than 600 degrees C were required. The use of a spray pyrolysis technique was successful in preparing both LiCoO2 and LiMn2O4 at substrates heated to temperatures as low as 400 degrees C. This temperature was probably not the actual synthesis temperature since thermal gravimetric experiments tend to indicate that our sol was capable of combustion synthesis.