Optical sensors for operando stress monitoring in lithium-based batteries containing solid-state or liquid electrolytes

Laura Albero Blanquer,Charlotte Gervillié,Fanny Bétermier,Florencia Marchini,Jiaqiang Huang,Jean-Marie Tarascon,Jan Roman Seitz,Nour Daher

doi:10.1038/s41467-022-28792-w

Abstract

The study of chemo-mechanical stress taking place in the electrodes of a battery during cycling is of paramount importance to extend the lifetime of the device. This aspect is particularly relevant for all-solid-state batteries where the stress can be transmitted across the device due to the stiff nature of the solid electrolyte. However, stress monitoring generally relies on sensors located outside of the battery, therefore providing information only at device level and failing to detect local changes. Here, we report a method to investigate the chemo-mechanical stress occurring at both positive and negative electrodes and at the electrode/electrolyte interface during battery operation. To such effect, optical fiber Bragg grating sensors were embedded inside coin and Swagelok cells containing either liquid or solid-state electrolyte. The optical signal was monitored during battery cycling, further translated into stress and correlated with the voltage profile. This work proposes an operando technique for stress monitoring with potential use in cell diagnosis and battery design.

Highlights

1,2, Fanny Bétermier[1,2,4], The study of chemo-mechanical stress taking place in the electrodes of a battery during cycling is of paramount importance to extend the lifetime of the device
When light travels through the optical fiber, the Fiber Bragg grating (FBG) sensor acts as a reflector for a specific wavelength, namely the Bragg wavelength which is defined as λB = 2neffΛ, where neff is the effective refractive index and Λ is the Bragg grating period (Fig. 1a, right)
Any temperature (T), hydraulic pressure (P), or strain (ε) change happening in the surroundings of the FBG sensor will modify either neff and/or Λ which will be translated into a variation in the reflected wavelength visualized as a peak shift (ΔλB)

Summary

Introduction

1,2, Fanny Bétermier[1,2,4], The study of chemo-mechanical stress taking place in the electrodes of a battery during cycling is of paramount importance to extend the lifetime of the device. This explains the ongoing efforts focused on (i) the development of new electrodes of higher capacity for electrochemical storage[4], (ii) new material morphologies and electrode structures for higher power rate[5], (iii) new chemistries for lowering the sustainability burden[2,6], and (iv) new cell architectures to enhance performance while increasing safety as it is the case of solid-state batteries[7] that arose the enthusiasm of our community The success of these approaches will depend on various and intertwined parameters: electronic and ionic transport processes, phase transformations, nature and dynamics of the interfaces, and their mechanical integrity. Such a wide use of FBGs is rooted in the numerous advantages that optical fibers offer like their reduced size (diameter ~150 μm) that makes them noninvasive, their chemical stability in various environments, and their immunity to electromagnetic interferences due to its electrically insulating nature[21]

Methods

Results

Conclusion