| Abstract: | Mn-based rechargeable aqueous zinc-ion batteries（ZIBs） are highly promising because of their high operating voltages, attractive energy densities, and eco-friendliness. However, the elec-trochemical performances of Mn-based cathodes usually su er from their serious structure transformation upon charge/discharge cycling. Herein, we report a layered sodium-ion/crystal water co-intercalated Birnessite cathode with the formula of Na0.55Mn2O4·0.57 H2O（NMOH） for high-performance aqueous ZIBs. A displacement/intercalation elec-trochemical mechanism was confirmed in the Mn-based cathode for the first time. Na+ and crystal water enlarge the interlayer distance to enhance the insertion of Zn2+, and some sodium ions are replaced with Zn2+ in the first cycle to further stabilize the layered structure for subse-quent reversible Zn2+/H+ insertion/extraction, resulting in exceptional specific capacities and satisfactory structural stabilities. Additionally, a pseudo-capacitance derived from the surface-adsorbed Na+ also contributes to the electrochemical performances. The NMOH cathode not only delivers high reversible capacities of 389.8 and 87.1 mA hg-1 at current densities of 200 and 1500 mAg-1, respectively, but also maintains a good long-cycling performance of 201.6 mA hg-1 at a high current density of 500 mA g-1 after 400 cycles, which makes the NMOH cathode competitive for practical applications. |
