An ultrafast Na-ion battery chemistry through coupling sustainable organic electrodes with modulated aqueous electrolytes

Rechargeable Na-ion batteries for grid-scale applications require key battery materials that couple high performance with sustainability. However, there are limited choices of electrodes and electrolytes to achieve this goal. Here we demonstrate that a sustainable organic electrode can deliver unprecedented electrochemical performance through coupling with a rationally designed hybrid electrolyte based on cost-efficient NaClO4, water, and weakly solvating additives (e.g., acetamide). We discover a new Na+ storage mechanism involving simultaneous structural and morphological changes of the organic electrode in the hybrid electrolyte. The unique combination of the organic electrode and hybrid electrolyte can facilitate unprecedented rate performance (>1000C), competitive and even superior to state-of-the-art fast-charging battery chemistries. We identify that the unique electrolyte chemistry enabled by the weakly solvating solvent can significantly promote electron transfer kinetics through the reorganization process, which was proven to be one key enabler for the high rate performance. The electrode and electrolyte chemistries elucidated in this work can propel the development of fast-charging battery technologies based on sustainable and low-cost materials.