Investigating Degradation Modes in Zn-AgO Aqueous Batteries with In-Situ X-ray Micro Computed Tomography
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 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 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 in-situ CT cells that can achieve >250 cycles at a high areal capacity of 12.5\;mAh/cm2. 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 4\;cm2 cells with electrochemically compatible current collectors. With this, we demonstrate over 325 cycles at a high capacity of 12.5\;mAh/cm2 for a 4\;cm2 form-factor. This work demonstrates that 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.