Effect of particle size in Li4Ti5O12 (LTO)-LiMn2O4 (LMO) batteries: a numerical simulation study

ROZENBLIT, A.; TORRES, W. R.; TESIO, A. Y.; CALVO, E. J.

JOURNAL OF SOLID STATE ELECTROCHEMISTRY (PRINT)

SPRINGER

Lugar: Wenheim; Año: 2021 vol. 25 p. 2395 - 2408

1432-8488

Multiscale numerical simulations based on the porous-electrode theory developed by Newman et al. have been carried outin COMSOL 5.4 environment for different particle sizes (PS) of LiMn2O4cathode material in Li4Ti5O12(LTO)-LiMn2O4(LMO) batteries. The electrolyte used in the simulations was 1.2 M LiPF6in a 3:7 wt % mixture of ethyl carbonate (EC)and ethyl methyl carbonate (EMC). The model has been validated against experimental data from the literature for half cells(LTO-Li and LMO-Li) and full LTO-LMO cells. A multiple-material model has been adapted to describe an LMO cathodeas a material blend with two PS (100 and 1000 nm radii), representing a binary PS distribution (PSD) within the material.The simulation results show that larger populations of small particles at constant cathode material load and constant currentdensity over the electroactive area can effectively allow for larger currents to be applied due to the compensating larger activesurface area per unit volume, which decreased the local current density at the LMO crystal interface with the electrolyte.However, higher overpotentials were obtained for cells with higher proportions of small particles, meaning that there is acompromise between electrical work output and C-rate. These findings highlight the importance of microstructure and PSin battery design, particularly in the LTO-LMO system