In Situ Deagglomeration of Cathode Particles in Electrode Slurries

Synthesis of single-crystal cathode materials for lithium-ion batteries usually results in secondary particles consisting of agglomerations of single crystal primary particles. Deagglomeration is required to obtain good electrochemical performance. Here a deagglomeration method is described where the secondary cathode particles are deagglomerated in situ during the electrode slurry making process. By this in situ slurry milling (ISM) method, the electrode slurry was dispersed while single-crystal lithium nickel manganese cobalt oxide (NMC) cathode particles were simultaneously fully deagglomerated by wet milling in NMP. Compared to dry milling methods, ISM was the most efficient at deagglomerating single-crystal NMC particles while inducing the least lattice microstrain. This resulted in ISM-processed NMC having improved electrochemical performance compared to NMC processed by dry methods. These results show the importance of particle deagglomeration and maintaining low lattice strain in obtaining good cathode cycling performance and that the described ISM method is effective for producing high performance deagglomerated cathode materials.