Effect of carbon blacks on electrical conduction and conductive binder domain of next-generation lithium-ion batteries

Abstract

High energy and power density are key requirements for next-generation lithium-ion batteries. One way to improve the former is to reduce the binder and conductive additive content. Carbon black is an important additive that facilitates electronic conduction in lithium-ion batteries and affects the conductive binder domain although it only occupies 5–8% of the electrode mass. However, the function of the structure of carbon black on short- and long-range electronic contacts and pores in the electrode is still not clear and has not been systematically researched in detail. In this work, five carbon blacks with different BET surface areas, oil absorption numbers and ordered graphitic carbon content were investigated. It was found that the ratio of disordered amorphous carbon to ordered graphitic carbon in carbon blacks strongly influences the short- and long-range electrical conduction, and the BET surface area highly affects the pore structure and ionic conductivity in the electrode. Its optimum ratio, indicated by the Raman density ID/IG, is 0.93–0.95. The recommended BET surface area was 130–200 m2/g for this experimental range. The results of this study can provide guidance for the screening of carbon blacks in the lithium-ion battery industry.