Sodium Dual-Ion Batteries with Concentrated Electrolytes

Na-based dual-ion batteries (DIBs) are a class of post-lithium technology with advantages including extremely fast charging, cost-effectiveness, and high natural abundance of raw materials. Operating up to high voltages (≈5.0 V), the decomposition of classic carbonate-based electrolyte formulations and the subsequent fade of capacity continues to be a major drawback in the development of these systems. Here, the performance of a Na-DIB was investigated in different commonly employed electrolyte system, and a highly concentrated (3 m NaPF₆ ) and fluorine-rich carbonate-based formulation was optimized to achieve a good performance when compared with literature (based on energy and power density, calculated at coin cell and only using the active mass of active materials).