Reducing Mass Transfer Effects on the Kinetics of 5V HE-NCM Electrode Materials for Li-Ion Batteries

Abstract

We report for the first time the use of a thin-layer electrode of HE-NCM, to study this material without the influence of kinetic limitations coming from the electrode engineering and to avoid the important problem of increasing pressure due to the gas release coming from the activation of Li 2MnO3 domains. Surprisingly, the overall kinetics of the electrode could not be improved by using thin layer electrodes. By using different techniques such as post mortem SEM/EDX, and electrochemical impedance spectroscopy we were able to find the cause of this kinetic limitation mainly due to the creation, during cycling, of a thick solid permeable interface layer coming from the electrolyte decomposition. Nevertheless, despite the kinetics of the electrode was not improved due to surface reaction, the cycling stability of the HE-NCM electrodes was improved. © 2014 The Electrochemical Society.