Effects of Chemical Dispersant and Wet Mechanical Milling Methods on Conductive Carbon Dispersion and Rate Capabilities of LiFePO4 Batteries

Abstract

AbstractThe dispersion state of conductive carbons in the cathodes of lithium ion batteries fabricated with a dispersant and with/without mechanical milling are considered with regard to the batteries' charge–discharge properties. Suspensions of Ketjen black (KB, EC 300J and EC 600JD) are dispersed in an organic solvent. Ball milling is then performed, modifying the particle sizes and structures. Results show improved dispersion but with collateral reduction of both maximum and average particle sizes. The more fragile EC 600JD, after ballmilling, is broken into more small segments than EC 300J, but with segment density high enough for loose coupling to form networks. Therefore, the electron conduction of EC600JD after ball milling is better than EC 300J. The high‐rate discharge capacity of EC600JD after ball milling is also better than that of EC 300J. However, rate capabilities decrease with increasing milling time.