A recent advancement may hold the key to overcoming a persistent problem in sodium-ion battery design. Researchers have discovered that slowing down the heating rate during the manufacturing process can prevent the development of microcracks in cathode particles, a longstanding issue that has impacted the longevity of these batteries.
Microcracks have historically compromised battery performance and shortened the lifespan of sodium-ion batteries. In response, a research team at Argonne explored the root cause by examining the structure of the cathode particles. These particles are built with a nickel-rich core surrounded by a shell made of cobalt and manganese. This design, which supports high storage capacity, also creates internal stress due to the material imbalance. During the charge and discharge cycles, this stress often results in cracks.
Through experiments, the researchers identified that adjusting the heating rate during cathode particle preparation could alleviate this internal tension. When the particles were heated at a more controlled rate of one degree per minute, no cracks developed. However, at a faster rate of five degrees per minute, cracks began to form once the temperature reached 482°F (250°C). This breakthrough could prove essential for the evolution of sodium-ion batteries, which are gaining interest as a cost-effective and plentiful alternative to lithium-ion batteries, particularly in renewable energy storage applications.
As they continue to refine this technology, the researchers are also exploring ways to eliminate nickel from the cathode composition entirely, aiming to cut costs and further boost the battery’s resilience. While sodium-ion batteries still offer lower energy density compared to lithium-ion models, they hold promise for electric vehicles designed for urban use, where extreme energy density is less critical. The long-term goal is to create sodium-ion batteries that rival the efficiency of current lithium iron phosphate cathodes, ultimately enhancing the sustainability of electric mobility.
Sodium-ion batteries work differently from the more common lithium-ion batteries. While lithium-ion technology relies on lithium ions moving between an anode and cathode to generate energy, sodium-ion batteries use sodium ions. This flow of sodium ions between electrodes during charging and discharging generates an electric current. Given the abundance and lower cost of sodium, sodium-ion batteries are seen as a practical solution for applications that need large-scale energy storage, such as power grids. The trade-off is that they currently store less energy per unit of weight or volume than lithium-ion batteries, but this discovery may bring these batteries closer to mainstream adoption.
This approach of controlling the heating rate in sodium-ion battery production may be an important step forward, promising enhanced durability and an extended lifespan. As the technology evolves, sodium-ion batteries could play a significant role in the shift towards cleaner energy solutions, especially for storage and urban transportation.
DG Innovate plc (LON:DGI) is an advanced research and development company pioneering sustainable and environmentally considerate improvements to electric mobility and storage, using abundant materials and the best engineering and scientific practices. Deregallera is a subsidiary of DG Innovate.
