Electrostatic heterocoagulation of carbon nanotubes and LiCoO₂ particles for a high-performance Li-ion cell

Nanotubes were coated on the surface of active LiCoO₂ particles using electrostatic heterocoagulation to enhance the electrochemical properties of a Li-ion battery. Only 0.5 wt% of multiwalled carbon nanotubes (MWCNTs) was added as a conducting agent into the LiCoO₂ cathode, which had a density of 4.0 g cm^-3. We found that our electrode that was prepared using heterocoagulation with 0.5 wt% of thin MWCNTs maintained a volumetric capacitance of 403mAhcm^-1 after 40 cycles from the initial 624mAhcm^-1, compared with previous result of 310mAhcm^-1 obtained from simple mixing with 3 wt% MWCNTs. The high volumetric capacity with smaller swelling using less amount of MWCNTs was attributed to the self-assembled nanotube network formed between active particles during coagulation, which was maintained with volume expansion during cycle testing.