Charge Transport Limitations to the Power Performance of LiNi 0.5 Mn 0.3 Co 0.2 O 2 Composite Electrodes with Carbon Nanotubes
Résumé
Electrode power performance is tied with electrode design that influences particularly the electronic wiring of the active mass and the speed of lithium salt diffusion in the pores. Improved capacity delivery, especially at 0 and 40°C was seen for NMC532 electrodes containing carbon nanotubes (CNT) comparatively to carbon black (CB). At low temperature CNT significantly increase the electrode conductivity as seen from the decrease of the polarization resistance. Furthermore, the analysis of the current density dependence of the discharge capacity with the Penetration Depth Model (PDM) reveal that the CNT improve the ionic transport at high temperature because they would minimize the effect of the PVdF swelling by the electrolyte and the resulting increase of the electrode tortuosity.