Effect of Post-Grinding and Heat Treatment on the Electrochemical Performance of NMC622 Li-Ion Battery Cathode Materials

Abstract

Given the increasing demands for high energy density lithium-ion batteries (LIBs), all cell components, particularly cathode materials, will need significant improvement in the future. Among the possible cathode materials for LIBs, NMC-based materials (LiNixMnyCozO2) have been receiving more attention due to their high energy density and low price. However, NMC-based cathode materials still suffer from degradation and capacity fading due to polarization and structural change over charge-discharge cycling which may be associated with, for example, cation mixing and particle morphology. Among these, the particle size of NMC-base cathodes plays an important role in degradation mechanism during long-term electrochemical cycling [1,2].The present study comprehensively highlights the effect of post-grinding methods and re-heating on electrochemical performance of Li-NMC622 cathode materials. For this purpose, NMC622 samples were synthesized using commercial precursors and different grinding methods were employed to break up the agglomerated secondary particles into smaller sizes. Accordingly, the microstructural, morphological, and electrochemical evolution of unground and ground samples were studied. Microscopy observations, along with electrochemical data, suggest that marked performance improvements can be achieved by controlling the particle size of NMC622 through post-grinding and heat treatment. References B. Huang et al., Solid State Ionics, 345, 115200 (2020).A. Liu et al., J. Electrochem. Soc., 168, 050506 (2021).