A New Design Strategy Enables High Mn‐Utilization Rate in Aqueous Zinc–Manganese Batteries: Constructing Cathodic Local Mn‐Rich Region

Abstract The deposition–dissolution mechanism with a two‐electron transfer reaction endows aqueous Zn–Mn batteries with a desirable theoretical energy density. However, due to the limited solubility of traditional manganese‐based materials and the competitive Mn shuttle behavior, the practical performance is unsatisfactory. Herein, by synergistically incorporating a novel Mn‐rich Mn 4 N cathode with a plasma functionalized carbon nanotubes film (PCNT) interlayer, an aqueous Zn–Mn battery with a high Mn‐utilization rate and high energy/power density is successfully developed. Specifically, the Mn 4 N cathode boasts high manganese content and dissolution activity, thereby offering a copious supply of Mn 2+ ions for the battery system. The PCNT interlayer, with abundant micropore structures and functional groups, not only restrains the Mn 2+ shuttle by entrapping the dissolved Mn 2+ but also offers copious reaction sites, ensuring concentrating Mn 2+ on the cathodic side and maximizing their contribution to the electrochemical reaction. Consequently, Mn 4 N‐PCNT exhibits a low polarization voltage and superior Mn‐utilization rate (64.8%). Without the MnSO 4 additive, Mn 4 N‐PCNT achieves an ultra‐high energy density of 821.9 W h kg −1 and remarkable long‐term cycling stability (90% capacity retention over 9000 cycles). The delightful results demonstrate the practical application potential of Mn 4 N‐PCNT and open up new avenues for the rational design of advanced Zn–Mn batteries.