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

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.

Electrochemo‐Mechanical Stresses and Their Measurements in Sulfide‐Based All‐Solid‐State Batteries: A Review

“…Reproduced according to the terms of the CC‐BY license. [ 16 ] Copyright 2022, The Authors, published by Springer Nature. i) Galvanostatic cycle (top), λ x and λ y evolution (middle), and operando stress evolution obtained internally by the FBG sensor and with the experimental calibration of the sensor (bottom).…”

“…Reproduced with permission. [ 16 ] Copyright 2022, The Authors, published by Springer Nature. e) The working principle of an FBG optical sensor.…”

“…Reproduced with permission. [ 16 ] Copyright 2022, The Authors, published by Springer Nature. f) The scheme of the birefringence phenomena in an FBG sensor when a relatively high external pressure is applied.…”

“…Reproduced according to the terms of the CC‐BY license. [ 16 ] Copyright 2022, The Authors, published by Springer Nature.…”

“…[ 14 ] Recently, the fiber Bragg grating (FBG) sensors, which are widely used in liquid LIBs, [ 15 ] have been implemented into the solid‐state battery system. [ 16 ] These in situ or operando measurements provide a powerful tool for examining the link between electromechanical effects and battery electrochemical performance. Recently, Song et al.…”