Latest research highlights a breakthrough in balancing conductivity and mechanical strength for sodium-ion batteries.
Solid-state sodium-ion batteries are gaining momentum in the race for safer, more efficient energy solutions. Researchers at Tohoku University, Japan alongside an international team, have developed a critical link between the mechanical robustness and ionic conductivity of sodium superionic conductors (NASICON). The research findings have proved to have the potential for advanced battery designs essential for future energy storage.
NASICON, known for its high ionic conductivity, has emerged as a promising candidate for battery applications. Industries such as electric vehicle manufacturers, renewable energy systems, and portable electronics stand to benefit greatly from these advancements, as the balance between stability, efficiency, and safety becomes increasingly vital. “We found that the most important factor was the relative density,” noted Eric Jianfeng Cheng, associate professor, Tohoku University. He explained that increasing NASICON’s density not only enhanced its ionic conductivity but also strengthened its mechanical properties, creating a dual advantage.
The researchers advocate advanced sintering techniques like spark plasma sintering (SPS) to optimise NASICON’s relative density. By employing these methods, defects such as pores can be minimised, improving both stability and performance. This approach also avoids the trade-offs seen with other strategies, such as enlarging grain size, which reduces resistance but compromises structural stability due to higher porosity.
Secondary phases, which add mechanical strength, often obstruct ionic flow, presenting another significant challenge. The study highlights that improving relative density uniquely enhances both ionic conductivity and mechanical strength—a synergy unmatched by other modifications.
The research also extends its implications beyond NASICON, suggesting potential applications for oxide-based solid electrolytes like garnet Li7La3Zr2O12 (LLZO). By offering a framework to harmonise these critical properties, the findings could propel the development of next-generation solid-state batteries.
This discovery underscores NASICON’s potential to reform energy storage technologies, providing safer and more efficient solutions for diverse applications, from electric vehicles to renewable energy grids.
