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.