Manganese oxide is a promising cathode material for rechargeable aqueous zinc-ion batteries (ZIBs). However, the low electronic conductivity and unstable structure evolution of manganese materials often result in poor rate performance and rapid capacity decay. Herein, we design N-doped Na2Mn3O7 (N-NMO) by combining sodium preintercalation and nitridation treatment strategies to stabilize the crystalline structure and reaction interface. Sodium preintercalation not only enlarges the interlayer distance for fast Zn2+ ion diffusion but also serves as a robust pillar to stabilize the crystalline structure during cycling. Meanwhile, the nitridation layer on the surface of Na2Mn3O7 particles is favorable for enhancing the electronic conductivity and inhibiting the cathode dissolution issue during repeated cycling. Consequently, the as-prepared N-NMO exhibits high reversible capacity (300 mAh g-1 at 0.2 A g-1), good rate capability (100 mAh g-1 at 10 A g-1), and outstanding long-term cycling stability (high capacity retention of 78.9% after 550 cycles at 2 A g-1). Considering the facile and simple synthesizing methods, the synergistic engineering of the interlayer structure and interface is expected to provide new opportunities for the development of high-performance Mn-based cathode materials for aqueous ZIBs.
Keywords: aqueous Zn-ion batteries; interface engineering; interlayer engineering; manganese oxides; nitrogen-doped.