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).

Controlling materials morphology, crystal phase and chemical composition at the atomic scale has become central in materials research. Wet chemistry approaches hold great potential in directing the material crystallisation process...