µ-Computer Tomography of Cathode Materials for All Solid-State Na Metal Batteries with Na-β″-Alumina Electrolyte

Lithium-ion batteries have long been the go-to choice for energy storage in mobile applications, thanks to their efficiency and reliability. However, as the global push for renewable energy intensifies and more power plants transition away from fossil fuels, concerns about lithium's limited availability have surfaced. Simply put, if all existing power plants were to switch to renewable sources, there wouldn't be enough lithium to go around for decarbonizing them all. This scarcity underscores the need to explore alternative storage solutions, with sodium batteries emerging as a promising contender.<br/>Researchers are increasingly turning their focus to sodium batteries due to their potential to overcome the limitations posed by lithium availability. This study delved into this area by conducting in-depth X-ray µ-computer tomography assessments on a specific type of sodium battery known as the sodium-nickel chloride (Na-NiCl₂) battery.<br/>The study's primary objective was to gain insights into the complex dynamics within the battery's cathode, which consists of a mixture of NaCl₂ and NaAlCl₄. The tomography findings unveiled a fascinating pattern of particle size distribution within the cathode material. Notably, the analysis revealed a concentration of fine-structured particles towards the side adjacent to the Na-β″-alumina electrolyte, while coarser particles were predominantly found near the current collector.<br/>This observed particle size distribution hints at the intricate interplay between the battery's various components during charge and discharge cycles. Specifically, it suggests that the electrolyte plays a crucial role in influencing the particle thinning process throughout these electrochemical reactions. Understanding and controlling this phenomenon are vital, as it could lead to challenges such as cathode cracking, especially during prolonged cycling periods.<br/>The possibility of cathode cracking is a significant concern, as it directly impacts the long-term performance and durability of sodium batteries. Addressing such challenges through ongoing research and technological advancements will be essential in ensuring the viability and widespread adoption of sodium batteries as part of a sustainable energy storage infrastructure. These efforts are crucial not only for meeting current energy demands but also for building a greener and more resilient energy ecosystem for the future.