Capacity-Fading Mechanisms of LiNiO[sub 2]-Based Lithium-Ion Batteries

Abstract

We used a suite of transmission electron microscopy (TEM) and associated electron spectroscopy methods to examine the local structure and changes in the electronic structure of positive electrode material. We found a scattered rock-salt phase near grain surfaces and grain boundaries, where turned to , deduced from relative intensity ratios and fine structures of the white-line peaks of the transition metals. The spatial distribution of the degraded phase throughout the secondary particle was found using a scanning TEM-electron energy loss spectroscopy spectral imaging technique and multivariate analysis. The degradation process and its relationship to the surface reactions with electrolytes is discussed based on the spatial-distribution map of the degraded phases.