Probing Electrochemical Strain Generation in Sodium Chromium Oxide (NaCrO2) Cathode in Na-ion Batteries during Charge/Discharge

07 November 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Sodium chromium oxide, NaCrO2, exhibits promising features as a cathode electrode in Na-ion batteries, yet it encounters challenges with its capacity fading and poor cycle life. NaCrO2 undergoes multiple phase transitions during Na ion intercalation, eventually leading to chemical instabilities and mechanical deformations. This study aims to investigate the reversible and irreversible mechanical deformations in NaCrO2 using an operando digital image correlation (DIC) coupled with electrochemical techniques. Electrochemical strains were recorded during either cyclic voltammetry or galvanostatic cycling. The electrode undergoes significant irreversible mechanical deformations in the initial cycle, and irreversibility decreases in the subsequent cycles. During desodiation and sodiation, the electrode initially undergoes volume contraction followed by expansion. The strain derivative peaks align well with the peak of the capacitive derivatives, indicating the phase-transition-induced deformations in the electrode. Cumulative irreversible strains demonstrate a linear relationship with the square root of cycling time, indicating irreversibility arising from forming a cathode-electrolyte interphase layer. The outcome of this study provides valuable insights into mechanical deformations in NaCrO2 electrodes during battery cycling and guides the design of mechanically robust cathodes for Na-ion batteries.

Keywords

sodium-ion batteries
NaCrO2 cathode
digital image correlation
phase transition
mechanical deformations.

Supplementary materials

Title
Description
Actions
Title
Supporting Information
Description
Supporting Information
Actions

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.