A Sodium‐Ion Battery with a Low‐Cost Cross‐Linked Gel‐Polymer Electrolyte

The design of a sodium‐ion rechargeable battery with an antimony anode, a Na 3 V 2 (PO 4 ) 3 cathode, and a low‐cost composite gel‐polymer electrolyte based on cross‐linked poly(methyl methacrylate) is reported. The application of an antimony anode, on replacement of the sodium metal that is commonly used in sodium‐ion half‐cells, reduces significantly the interfacial resistance and charge transfer resistance of a sodium‐ion battery, which enables a smaller polarization for a sodium‐ion full‐cell Sb/Na 3 V 2 (PO 4 ) 3 running at relatively high charge and discharge rates. The incorporation of the gel‐polymer electrolyte is beneficial to maintain stable interfaces between the electrolyte and the electrodes of the sodium‐ion battery at elevated temperature. When running at 60 °C, the sodium‐ion full‐cell Sb/Na 3 V 2 (PO 4 ) 3 with the gel‐polymer electrolyte exhibits superior cycling stability compared to a battery with the conventional liquid electrolyte.