Iron-based sodium-ion full batteries

Rechargeable sodium-ion batteries have been an active area of research over the past several years. While a great deal of attention is now focused on the development and evaluation of single electrode materials, much less is paid to their combined performance in full batteries. Most full batteries currently available suffer from rapid capacity fading under extended cycling. In this study, we prepare ultra-small, poorly crystalline FeOx nanoparticles supported on carbon nanotubes as the anode material for sodium-ion batteries. It exhibits excellent half-cell performances; and, when combined with a Prussian blue cathode material, it leads to iron-based full batteries. Our prototypes have a working voltage of similar to 2 V, specific energy density of similar to 136 W h kg-1 and, most impressively, outstanding cycling stability at both low and high current rates with negligible capacity loss. Owing to their low material and fabrication cost, long cycle life and high efficiency, we believe that these iron-based sodium-ion batteries would be highly appealing toward the stationary energy storage.