Understanding Electrochemical-Acoustic-Time-of-Flight Analysis and Materials for Energy Storage

Abstract

Recent developments in the mechanical understanding of electrochemical energy storage devices have shown the potential of using ultrasonic pulses in monitoring physical changes in electrochemical cells and the ability to correlate those changes with the state-of-charge and state-of-health of the cell. This electrochemical acoustic time-of-flight (EAToF) technique has been used to study several battery chemistries including zinc alkaline and lithium ion but it is still not fully understood how the changes in acoustic response represent the varying electrochemical reaction mechanisms. This study presents a comparison of EAToF characterizations of various battery chemistries with varying electrochemical reaction mechanisms (intercalation, dissolution/reprecipitation, phase change). The study will utilize in operando EAToF analyses, ex situ and in situ characterizations of battery components, and acoustic models to directly correlate trends in the EAToF analyses with the fundamental electrochemical material processes that occur in each battery chemistry. The resulting work not only provides a novel approach to the characterization of electrochemical materials, but also demonstrates the viability of the EAToF technique for industrial use as a monitor of the state of health in energy storage systems.