High‐safety and low‐cost aqueous zinc‐ion batteries (ZIBs) are an exceptionally compelling technology for grid‐scale energy storage, whereas the corrosion, hydrogen evolution reaction and dendrites growth of Zn anodes plague their...

The dendrite issues associated with zinc anode lead to safety hazards and sluggish reaction kinetics, and largely restrain widespread application of aqueous zinc ion batteries (ZIBs). Herein, a functional separator composed of cellulose nanofibers and graphene oxide (CG) is developed for dendrite‐free and exceptionally stable ZIBs, realized by uniform hexagonal zinc deposits with manipulated crystallographic orientation (002) plane. This CG separator with negative surface charges and abundant zincophilic‐O groups ensures the strong interaction between the separator and zinc species, simultaneously inducing Zn(002) deposition due to the low mismatch between (002)Zn and (002)GO, thus initiating the preferential orientation of the zinc growth along the horizontal direction due to strong Zn binding ability, and uniform interfacial charge of Zn(002) deposition. Furthermore, the CG separator can effectively promote the uniform nucleation of Zn2+ and eliminate side effects. Accordingly, extremely low polarization of 58 mV at 0.5 mA cm−2, and ultralong cycle life over 1750 h at 2 mA cm−2 and 400 h at 20 mA cm−2 are achieved for the zinc anode. Notably, the CG separator significantly boosts rate capability and cyclability of coin‐type full batteries (Zn||Zn(CF3SO3)2||V2O5, Zn||ZnSO4+MnSO4||MnO2/graphite) and a flexible soft‐packaged battery (Zn||MnO2). Therefore, this work introduces a sustainability consideration in to the design of separators for constructing dendrite‐free ZIBs.

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Manganese-based materials are considered potential cathode materials for aqueous zinc ion batteries (ZIBs). However, the dissolution of manganese leading to an abrupt decline of capacity and the sluggish electrochemical reaction kinetics are still the main bottlenecks restricting their further development. Herein, a NiMn-layered double hydroxide-derived Ni-doped Mn 2 O 3 (NM) is developed to suppress the dissolution of manganese. The incorporation of Ni 2+ can promote electronic rearrangement and enhance the conductivity, ultimately improving the reaction kinetics and electrochemical performance of the NM. Moreover, the doped Ni 2+ can effectively stabilize the MnO bond of Mn 2 O 3 by reducing the formation energy. In addition, the storage mechanism based on the simultaneous insertion and transformation of H + and Zn 2+ is demonstrated. Interestingly, the Ni-doped Mn 2 O 3 shows a high specific capacity of 252 mAh g-1 (0.1 A g-1), three times more than the pure Mn 2 O 3 (72 mAh g-1). The capacity retention (≈85.6% over 2500 cycles at 1.0 A g-1) is also more excellent when comparing with the Mn 2 O 3 cathode (≈49.7%). Significantly, an ultra-high energy density of 327.6 Wh kg-1 has been achieved using Ni-doped Mn 2 O 3 cathode, which suggests that the synergistic effect of manganese and other transition metal ions provide a promising strategy for future development of ZIBs.

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