Intensive powder mixing for dry dispersing of carbon black and its relevance for lithium-ion battery cathodes

Abstract

Carbon black is an important component in lithium-ion battery electrodes since it significantly improves the electric conductivity in the coating. Dependent on the carbon black structure and the homogeneity of the carbon black distribution, electrical and electrochemical electrode properties vary. The presented work reveals that the carbon black structure in lithium-ion battery electrodes can precisely be governed by careful parameter variations in an upstream dry mixing process. Significant changes in important electrode properties like mechanical, structural and electrical characteristics are achieved and can be described as functions of the process parameters “mixing time” and “mixing intensity”. The integration of an intensive dry mixing process improves the coating homogeneity and creates short-range electrical contacts on the particle surfaces, leading to enhancements in cycling stability. Long-range electrical contacts can be re-established due to a subsequent calendering step, compensating rate capability losses, which can be identified for uncalendered electrodes.