Rechargeable Seawater Batteries Based on Polyimide Anodes

Being nearly unlimited natural resource containing mostly Na cations, the use of seawater as an electrolyte solution (aka seawater batteries) for electrochemical energy storage has received growing attention. To date, the vast majority of studies have focused on the use of seawater in Na-metal batteries protected by ion-conductive membranes hermetic to water. These systems, however, are complex and expensive, and suffer from a short cycling life. Here, we present alternative seawater batteries that utilize polyimide anodes. With its high capacity of more than 140 mAh/g, impressive rate capability, and excellent long-term stability (98% capacity retention after more than 9000 cycles), the prepared polyimide electrodes demonstrated to be promising candidate anodes for seawater electrochemical energy storage devices. Looking for a suitable cathode, we explored the use of nickel hexacyanoferrate (Ni-HCF) and activated carbon. Our findings suggest an innovative approach to design sustainable and cost-effective systems for large-scale energy storage.