A research team at the University of Surrey develops 28 sodium-ion battery materials to enhance charging speed and endurance.

Researchers at the University of Surrey have developed a database containing 28 materials to assist in identifying better candidates for sodium-ion battery construction. This database aids in the search for alternative materials to replace traditional lithium-ion batteries, as lithium resources are relatively scarce and unevenly distributed. Daniel Komandur, a lecturer at the University of Surrey's Department of Chemistry and Chemical Engineering and the corresponding author of the study, stated, "We are heavily reliant on lithium-ion batteries, but lithium resources are relatively scarce and unevenly distributed globally." He noted that sodium-ion batteries are gradually becoming a reliable alternative technology; however, further analysis is needed to improve their performance and energy storage capacity during repeated charging cycles.

He added, "The abundance of sodium makes sodium-ion batteries an important technological development."

The Potential of Sodium-Ion Batteries

The team explored how to improve the performance of sodium manganese oxide as a cathode by altering its chemical composition. This key battery component determines how much energy the battery can store and its operational efficiency. During their investigation, they created a database composed of 28 different metal compositions and compared their performance in sodium-ion batteries. This series of materials was produced by substituting manganese with varying amounts of different metals, including iron, titanium, and vanadium. The research found that iron can enhance energy storage capacity, vanadium can improve cycling stability, and small amounts of titanium can boost high-rate performance.

Some titanium-containing materials retain over 90% of their capacity after 100 charge-discharge cycles.

Machine Learning Accelerates Material Exploration

The team unanimously agreed that finding materials that provide optimal performance is a significant challenge. To explore suitable alternative materials, the researchers developed an automated approach to analyze data generated from experiments. They trained machine learning models using datasets produced during experiments. Komandur stated, "This work is the first step in building a larger dataset, which is crucial for machine learning-guided material searches, helping us more quickly identify promising materials and accelerate the development of better sodium-ion batteries."

The researchers indicated that expanding the dataset will ultimately enable artificial intelligence to predict promising battery compositions before material production and experimentation. However, the current database is still too small for reliable predictions. Expanding the approach to a broader range of cathode materials could generate the large, high-quality datasets needed to accelerate the discovery of new battery materials. Over time, this will help scientists design sodium-ion cathodes tailored to specific needs, such as higher energy storage, faster charging, or longer lifespan. Eden Marks, a co-lead author of the study and a PhD student in Space Engineering, stated, "What is most striking is how relatively small changes in composition affect the balance between energy storage capacity, high-rate performance, and durability."

Mapping these relationships gives us a clearer direction for the next steps in exploration."

The findings of this research have been published in a new study in the Journal of Materials Chemistry.