Investigating Degradation Modes in Zn-AgO Aqueous Batteries with $\textit{In-Situ}$ X-ray Micro Computed Tomography

TL;DR

This study uses in-situ X-ray micro-CT to investigate degradation mechanisms in Zn-AgO aqueous batteries over long cycles, revealing effects of parasitic gassing and enabling the development of larger, high-capacity cells with improved longevity.

Contribution

The paper demonstrates the application of in-situ X-ray micro-CT to study long-term degradation in Zn-AgO batteries and develops larger cells with extended cycle life based on these insights.

Findings

Over 250 cycles achieved in small cells at high capacity

Parasitic gassing impacts current collector stability

Larger 4 cm² cells sustain over 325 cycles with high capacity

Abstract

To meet growing energy demands, degradation mechanisms of energy storage devices must be better understood. As a non-destructive tool, X-ray Computed Tomography (CT) has been increasingly used by the battery community to perform $\textit{in-situ}$ experiments that can investigate dynamic phenomena. However, few have used X-ray CT to study representative battery systems over long cycle lifetimes (>100 cycles). Here, we report the $\textit{in-situ}$ CT study of Zn-Ag batteries and demonstrate the effects of current collector parasitic gassing over long-term storage and cycling. We design performance representative $\textit{in-situ}$ CT cells that can achieve >250 cycles at a high areal capacity of $\mathrm{12.5\;mAh/cm^2}$. Combined with electrochemical experiments, the effects of current collector parasitic gassing are revealed with micro-scale CT (MicroCT). The volume expansion and evolution of ZnO and Zn depletion is quantified with cycling and elevated temperature testing. The experimental insights are then utilized to develop larger form-factor $\mathrm{4\;cm^2}$ cells with electrochemically compatible current collectors. With this, we demonstrate over 325 cycles at a high capacity of $\mathrm{12.5\;mAh/cm^2}$ for a $\mathrm{4\;cm^2}$ form-factor. This work demonstrates that $\textit{in-situ}$ X-ray CT used in long cycle-lifetime studies can be applied to examine a multitude of other battery chemistries to improve their performances.