Salt tweak gives sodium batteries 500 cycles and 70% retention

Researchers from Lingnan University, in collaboration with Tsinghua University and the Beijing Institute of Technology, have developed an improved sodium battery that overcomes key limitations such as instability, short circuits, and rapid capacity loss during fast charging. By simply increasing the salt concentration in the electrolyte, the team was able to control sodium ion deposition more smoothly, preventing dendrite formation that typically damages sodium batteries. This adjustment enabled the battery to achieve fast charging speeds of 10C (charging in minutes) and maintain over 70% capacity retention after 500 charge-discharge cycles, marking a significant durability milestone. The innovation hinges on shifting the deposition kinetics from diffusion-controlled to charge-transfer-controlled, enhancing safety and longevity without the presence of metallic sodium in the fully discharged state. Sodium offers advantages over lithium due to its abundance, lower cost (less than a tenth of lithium), and environmental benefits, potentially reducing the cost of electric vehicles and grid storage solutions. However, challenges remain, including the need to further extend cycle life