Deriving the numerical value of LIB mathematical model parameters from experiments: Case of as-formed and aged NMC/LMO cathodes

This study presents an experimental approach to the parameterization of lithium-ion battery cathodes for the Pseudo-Two-Dimensional (P2D) model, focusing on blended NMC532/LMO, commonly used in automotive batteries. Specifically, we are proposing an Experimental Battery Parameterization (EBP) protocol to determine key material parameters through direct measurement rather than relying on literature values. The research examines as-formed and aged cathodes, revealing significant changes in electrochemical behaviour, structural integrity, and material composition after ageing. Ageing effects, such as particle fracture, increased lithium content, and changes in porosity and conductivity, were observed. While as-formed cathodes showed higher theoretical capacities, aged ones exhibited lower activation energies for lithium diffusion, indicating enhanced ion mobility, accompanied by structural degradation. Our study emphasizes that experimental parameterization, especially in the case of aged batteries, is essential to have a precise grasp over the scope and limitations of the P2D model and identify areas for model improvement.