High capacity aqueous periodate batteries featuring a nine-electron transfer process

We present sodium manganese periodate (NaMnIO₆)as a novel cathode material, which exhibited a nine-electron discharge process, for the development of high-performance aqueous battery systems. Purified carbon nanotubes (CNTs)were selected as conductive cathode additive. Along with an anion exchange membrane, acid-salt water dual electrolytes were used to reduce anode corrosion. NaMnIO₆ showed a specific capacity as high as 750 mAh g⁻¹ in prototype batteries, which was nearly 94% of the theoretical capacity. Different anode metals were studied and the Mg system showed the highest specific energy of 746 Wh kg⁻¹. Furthermore, these batteries fabricated using 3D-printed casings also feature replaceable electrodes once they are consumed.