NANOSCALE CHARACTERIZATION OF THIN FILM Li1.2Mn0.54Ni0.13Co0.13O2 CATHODE IN LITHIUM ION BATTERIES BY USING SCANNING PROBE MICROSCOPY TECHNIQUES

Abstract

The widely-used lithium-ion batteries (LIBs) have many advantages, such as non-memory effect, long cycle life, good portability, and high energy conversion efficiency. These features make them the most attractive power sources for portable electronic products, electric vehicles and energy storage systems. Up to now, most of studies are focused on the understanding of the functionalities of the LIBs at device level and atomic level. The knowledge at mesoscopic level has yet to be understood thoroughly. Scanning probe microscopy (SPM) based techniques are therefore powerful tools to investigate the detailed phenomenon associated with lithium ion diffusion in LIBs materials at mesoscopic level. Hence, the aim of the present study is to extend the applications of SPM techniques in the study of LIB materials. This thesis has covered explorative studies on nanoscale characterization of Li1.2Co0.13Ni0.13Mn0.54O2 thin film cathode, using a combination of various SPM techniques, i.e. Atomic Force Microscopy (AFM), Electrochemical Strain Microscopy (ESM) with dual AC resonance tracking (DART) and Band Excitation (BE), conductive-AFM (c-AFM), Biased-AFM, and AM-FM (Amplitude Modulation-Frequency Modulation). This study has taken the first step in characterizing Li1.2Co0.13Ni0.13Mn0.54O2 cathode by using the SPM-based techniques. The findings of this study are of considerable importance since they provide a new perspective and novel method to understand this cathode material at the mesoscopic length scale, bridging the gap between atomic and device-level studies.