# Operando Raman spectroscopy for investigating lithium deposition/dissolution and diffusion at the microelectrode surface

## TL;DR

This paper introduces a new Raman spectroscopy method to study lithium behavior at microelectrodes in lithium-ion batteries.

## Contribution

The novel operando Raman spectroscopy method enables real-time visualization of lithium deposition and dissolution processes at microelectrode interfaces.

## Key findings

- Lithium deposition releases free EC and FSA molecules at the interface.
- Dissolution promotes rapid Li+ coordination.
- The observed diffusion layer thickness aligns with theoretical predictions.

## Abstract

We developed an operando Raman spectroscopy method to visualize lithium deposition and diffusion at the microelectrode interface. Lithium deposition released free EC and FSA, while dissolution promoted rapid Li+ coordination. The estimated diffusion layer thickness matched theoretical predictions, highlighting micro-Raman spectroscopy's potential for studying lithium-ion battery interfaces.

Operando Raman spectroscopy was developed to visualize interfacial reactions at a microelectrode, revealing environmental changes during Li deposition/dissolution and enabling analysis of dynamic battery interface processes.