Particle Interaction and Aggregation in Cathode Material of Li-Ion Batteries: A Numerical Study

Aggregation between additive particles and active particles in the electrode material of batteries strongly affects their interfacial impedance and power performance. This paper proposes a three dimensional model to simulate the aggregation process of carbon black (CB) and LiMn2O4 active material (AM) particles within a liquid medium (PVDF polymer dissolved in NMP solvent). Brownian dynamics is employed in the simulation and the resulting aggregates are characterized by the number of CB particles connected to the percolated cluster of AM. The effects of the particle size, CB/AM mass ratio and temperature are investigated. It is found that a larger AM particle size and larger CB/AM mass ratios each contributes positively to the percentage of CB attachment. However, with increasing temperature this percentage increases in cases where AM particles have a diameter of 1 mu m but decreases for AM particles whose diameter is 0.5 mu m. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3625286] All rights reserved.