Nanoscale characterization of charged/discharged lithium-rich thin film cathode by scanning probe microscopy techniques

Lithium ion intercalation and de-intercalation at electrodes are critically issues for development of the high performance Li-ion batteries. However, the changes of the surface morphologies, electrical and mechanical properties during the charge/discharge cycles are still not well understood. In this study, by using Atomic Force Microscopy (AFM), Electrochemical Strain Microscopy (ESM), AM-FM (Amplitude Modulation - Frequency Modulation), and conductive AFM (c-AFM) techniques, we have studied the significant changes, with nanoscale resolution, on the surface topography, electrochemical deformation, stiffness/elastic modulus, and electronic conductivity of Li-rich layered oxide cathode under the first cycle of galvonostatic charging/discharging process. This study has established the relationship between the nanoscale morphology and properties variations and the macroscopic charge/discharge processes for the Li-rich layered oxide cathode material, and the results also prove the feasibility of combining various Scanning Probe Microscopy (SPM) based techniques on the studies of lithium ion battery materials. (C) 2017 Elsevier B.V. All rights reserved.