Micro-Measurement and Microanalysis System for Electrode Reactions in Lithium-Ion Batteries

Abstract

The performance of Li ion batteries is highly dependent on the thermodynamics and kinetics of electrode reactions. If the reactions and mechanisms in or across the interfaces of electrode materials can be resolved, the better electrode design may be achieved and then the electrochemical behavior and performance of Li ion batteries may be further improved.The electrochemical impedance spectroscopy (EIS) is a common analytical tool in the study of Li ion diffusion in the battery. EIS measures the impedance responses of the electrochemical cell under a range of AC frequencies; and the diffusion mechanisms of Li ions are investigated by the construction of theequivalent circuit models. However, the complexity in the circuit models makes it difficult to resolve the individual interfacial reaction; recent development of micro-electrodes help to resolve some of these issues, but it fails to effectively measure reactions between materials and interfaces due to the restrictions in the conventional experimental setting. Thus, the objective of this work is to investigate the electrochemical reaction on a thin film of oxide electrodes such as LiCoO2 and/or Li4Ti5O12for lithium ion battery applications. The measurements and analysis will be conducted based on the scanning impedance microscopy (SIM) techniques, and the self-developed multi-electrode AFM probes.A novel approach will be used to integrate AFM probe into the assembly of an advanced solid-state thin film lithium ion battery, to establish a micro/nano-scale battery measurement and analysis system.