Strategic dispersion of carbon black and its application to ink-jet-printed lithium cobalt oxide electrodes for lithium ion batteries

摘要

The effects of surface-modified carbon black induced by UV/ozone and triethylenetetramine on the microstructure and electrochemical properties of ink-jet-printed LiCoO_2 electrodes for lithium ion batteries are observed. The dispersion properties of surface-modified carbon black and LiCoO_2 ink are evaluated using particle size distribution measurements, surface pressure calculations, and scanning electron microscopy. Modifications to the surface of carbon black result in improved dispersion properties, which in turn enhance the compactness and homogeneity of the microstructure of ink-jet-printed LiCoO_2 electrodes compared to those printed with as-received carbon black. Electrochemical experiments indicate that LiCoO_2 electrodes ink-jet-printed with surface-modified carbon black exhibit improved initial specific discharge capacities compared to those printed with as-received carbon black due to the better electrical contact between the carbon black and the LiCoO_2, as evidenced by the analysis of the area-specific impedance of the electrode as a function of the depth of discharge.