Correlating Electrochemical Kinetic Parameters of Single LiNi_(1/3)Mn_(1/3)Co_(1/3)O2 Particles with the Performance of Corresponding Porous Electrodes

摘要

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(io)from electrochemical impedance measurements.We find that the carbon coating on the LiN_(1/3)Mn_(1/3)Co_(1/3)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.