Preparation and characteristics of LiCoO2 paste electrodes for lithium ion micro-batteries

The thick film electrodes (cathode) have been developed via screen printing using LiCoO2 paste to improve the discharge capacity of lithium ion micro-batteries. The LiCoO2 pastes were formulated using the mixtures of LiCoO2 powder as a functional material, carbon black as a conducting agent, ethyl cellulose and terpineol as a vehicle, and Emphos PS-21A as a dispersant. Depending on the amount of carbon black, the average and maximum surface roughnesses varied from 0.54 to 1.00 mu m and 6.2 to 18.7 mu m respectively. The internal resistance in the paste electrodes could also be controlled to 120 K Omega cm(-2) by the addition of carbon black in the pastes. The thickness of the printed film is independent of the paste composition, but it decreased from 15 to 6 mu m with the increase in screen mesh number from 250 to 500. The initial specific discharge capacity of the printed cathode which was prepared using the mixture Ag-coated LiCoO2 powder improved to 180 mu Ahcm(-2).