Correlating Electrochemical Kinetic Parameters of Single LiNi1/3 Mn1/3 Co1/3 O2 Particles with the Performance of Corresponding Porous Electrodes.

Abstract

Characterizing microscale single particles directly is requested for dissecting the performance-limiting factors at the electrode scale. In this work, we build a single-particle electrochemical setup and develop a physics-based model for extracting the solid-phase diffusion coefficient (Ds ) and exchange current density (i0 ) from electrochemical impedance measurements. We find that the carbon coating on the LiNi1/3 Mn1/3 Co1/3 O2 surface enhances i0 . In addition, Ds and i0 decay irreversibly by ≈25 % and ≈10 %, respectively, when the cutoff charge voltage increases from 4.3 V to 4.4 V. Moreover, we correlate intrinsic parameters of single particles with the performance of porous electrodes. Porous electrodes assembled with active particles with higher i0 values deliver a greater capacity and faster capacity fade. The methods developed in this combined experimental and theoretical work can be useful in correlating the single-particle scale and porous-electrode scale for other similar systems.