Limited selectivity cathode additive for high-capacity and long-life aqueous Zn-MnO2 batteries

Despite their attractive cost and safety, achieving long-cycle-life aqueous Zn-MnO 2 batteries is still hindered by complex interfacial Mn chemistry, particularly Mn 2+ dissolution/redistribution that accelerates performance decay. The capacity of MnO 2 originates from the insertion and conversion of Zn 2+ , yet Mn 2+ dissolution has consistently been a critical factor undermining the performance of MnO 2 cathodes. Therefore, achieving simultaneous enrichment of Zn 2+ and Mn 2+ on the cathode surface remains a pressing need in aqueous Zn-MnO 2 batteries. In this work, an amide-based compound, N, N′-1,2-Ethanediylbis(benzamide) (EDB) is proposed as the cathode additive to exhibit limited selectivity in chelating both Zn 2+ and Mn 2+ ions on the surface of MnO 2 cathode, thereby synergistically enriching interfacial ions to boost capacity utilization and suppress Mn dissolution, leading to enhanced cycling stability. The Zn||EDB@MnO 2 cell exhibits a high specific discharge capacity of 465 mA h g −1 after 200 cycles at 308 mA g −1 , and excellent long-term cycling stability with retaining 83% of its initial capacity after 1000 cycles at 5 A g −1 . This study on cathode additives presents a novel and effective strategy for achieving high-capacity and long-cycle-life aqueous Zn-MnO 2 batteries, while also offering valuable insights into the design of functional additives for advanced energy storage systems facing challenges related to interfacial adsorption and surface-mediated reactions on electrodes.