Researchers have developed a groundbreaking solid-state sodium-ion battery, a technology poised to make electric vehicles and grid-scale energy storage safer and more affordable. By replacing the flammable liquid electrolytes found in conventional lithium-ion batteries with a novel solid material, scientists have mitigated the risk of “thermal runaway” that can lead to fires. This innovation could accelerate the adoption of more sustainable energy solutions by offering a stable, cost-effective alternative built from the more abundant element, sodium, as detailed in recent studies published in *Advanced Materials* and *Advanced Functional Materials*.
The prevailing lithium-ion batteries, used in everything from smartphones to electric cars, carry an inherent risk of a dangerous chain reaction known as “thermal runaway.” This phenomenon, often triggered by damage or short-circuiting, can cause the highly flammable organic liquid electrolytes within the battery to ignite, leading to fires or explosions. In a significant step toward a safer alternative, researchers have engineered a solid-state sodium-ion battery that utilizes a non-flammable solid electrolyte composed of sulfur and chlorine, effectively eliminating this critical safety hazard.
The newly developed battery has demonstrated impressive performance, maintaining a Coulombic efficiency of 99.26% after 600 charging cycles, a figure that approaches the high standards set by commercial lithium-ion technology. “We replaced the liquid electrolyte in the battery into a solid-state electrolyte — it’s non-flammable,” explained Yang Zhao, a professor at Western University. To validate their findings, the team employed Canada’s national synchrotron facility, the Canadian Light Source, to observe ion movement within the solid material, confirming its high conductivity and structural integrity.
This advance could pave the way for the widespread adoption of sodium-ion batteries, particularly in critical applications like national battery energy storage systems (BESS). Concerns over fires at such facilities have slowed their deployment, but a more stable battery chemistry could ease safety fears. Furthermore, sodium is significantly more abundant than lithium, which could dramatically lower the cost of the global battery supply chain. Sodium-ion batteries also offer environmental benefits, as they are easier to recycle and contain fewer hazardous materials.
The potential of sodium-ion technology has not gone unnoticed by the industry. The world’s largest battery producer, CATL, has already announced mass production of its sodium-ion batteries, with plans to integrate them into cars by 2026. Similarly, Chinese automotive and battery giant BYD is actively developing sodium-ion systems for large-scale grid storage. The primary challenge for researchers now is to scale up manufacturing while maintaining a balance between safety, energy density, and a long operational lifespan.