High-performance aqueous rechargeable sulfate- and sodium-ion battery based on polypyrrole-MWCNT core-shell nanowires and Na0.44MnO2 nanorods

Aqueous rechargeable sodium-ion batteries (ARSBs) have the potential for application in large-scale electric energy storage systems owing to the safety of the non-flammable aqueous electrolyte and the natural abundance of sodium resources. Herein, we demonstrate the high performance of an aqueous rechargeable sulfate- and sodium-ion battery based on a MWCNT-polypyrrole core–shell nanowire anode and a Na0.44MnO2 nanorod cathode in a 1 M aqueous Na2SO4 electrolyte. Because the charge-discharge process involves the simultaneous uptake and release of both sulfate anions and sodium cations, it offers a wider choice of electrode materials for use at high voltages. The MWCNT-polypyrrole core-shell nanowire//Na0.44MnO2 nanorod full cell delivered excellent discharge capacities of 99.2 mA h g−1 and 87.2 mA h g−1 with a high voltage of 1.6 V at the charge-discharge current densities of 100 mA g−1 and 3000 mA g−1, respectively. When compared with previous ARSBs, the aqueous rechargeable sulfate- and sodium-ion battery shows much better performance at relatively high charge–discharge rates, making it suitable for large-scale energy storage applications.