High energy X-ray imaging of heterogeneity in charged and discharged lead-acid battery electrodes

Lead-acid battery technology continues to form a critical part of the global electrochemical energy storage market. Part of the reason for the lead-acid battery's success is due to its well understood electrochemistry. However, over recent years it has become clear that a poor understanding of inherent heterogeneity in chemical changes that happen during the charge and discharge cycles of these batteries is limiting innovation. In this paper we show that high-energy X-rays can be used to better understand how the chemistry within these systems is localised spatially, and how it affects battery performance. Used commercial lead-acid battery electrodes were sampled then imaged before and after the Pb K-edge (88 keV). In these electrodes, multiple features associated with battery failure were clearly observed throughout each electrode. A custom-made lead-acid battery was also imaged in-operando. Inhomogeneous utilization of the negative electrode arising from charge-transport effects could be clearly observed in the electrode face. These results show that high-energy X-ray imaging could be a powerful tool to better understand the relationship between the spatial and electrochemical dimensions in lead-acid batteries.

Automated summary

This study demonstrates that high-energy X-ray imaging can be used to investigate the spatial and electrochemical dimensions in lead-acid batteries. The imaging results show the presence of multiple features associated with battery failure and reveal the inhomogeneous utilization of the negative electrode. This technique provides valuable insights into the relationship between chemistry and performance in lead-acid batteries.