Mn₃O₄@NC Composite Nanorods as a Cathode for Rechargeable Aqueous Zn‐Ion Batteries

Abstract

Rechargeable aqueous zinc-ion batteries (ZIBs) have attracted escalating attention recently, owing to their energy density, decreasing cost, advanced safety, and environmental benignity. Nevertheless, ZIBs still lack suitable cathode materials with stable cycling performance, owing to the high polarization of zinc ion. Therefore, developing candidate materials with excellent properties remains a great challenge. Herein, we successfully synthesize a novel Mn 3 O 4 @N-doped carbon matrix composite nanorods (Mn 3 O 4 @NC Nrs) by using MnOOH nano-rods (the self-sacrifice templates) and polypyrrole (carbon and nitrogen source). Benefiting from the N-doped carbon shell and the synergetic effect of Zn 2 + and Mn 2 + in the electrolyte, the Mn 3 O 4 @NC Nrs show superior cycling stability and long cycling features for ZIBs. Specifically, the zinc cell conducts a high reversible capacity of 280 mAh g À 1 at 100 mA g À 1 and retains a high reversible capacity of 97 mAh g À 1 at 1000 mA g À 1 after 700 cycles. In addition, the work provides a new approach to fabricate long-term and high-rate capability cathodes for ZIBs.[a] M.

MnO2 Nanosheet‐Assembled Hollow Polyhedron Grown on Carbon Cloth for Flexible Aqueous Zinc‐Ion Batteries

“…[27] In addition, structurale ngineering of electrode materials is an effective method to improve their electrochemical activity and kinetics. [33][34][35] For instance, Liu and co-workerss ynthesized Mn 3 O 4 nanorods coated with nitrogen-doped carbon matrix, which delivered high reversible capacity of 97.0 mAh g À1 at 1.0 Ag À1 after 700 cycles. [33] The improved electrochemical performance was attributed to the nitrogen-doped carbon shell and the synergetic effect of Zn 2 + and Mn 2 + in the electrolyte.…”

“…[33][34][35] For instance, Liu and co-workerss ynthesized Mn 3 O 4 nanorods coated with nitrogen-doped carbon matrix, which delivered high reversible capacity of 97.0 mAh g À1 at 1.0 Ag À1 after 700 cycles. [33] The improved electrochemical performance was attributed to the nitrogen-doped carbon shell and the synergetic effect of Zn 2 + and Mn 2 + in the electrolyte. Chen and co-workers reported the construction of cation defects in spinel ZnMn 2 O 4 ,w hichg reatlyi mprovedt he cycling stabilitya nd resulted in ad ischarge capacity of 150.0 mAh g À1 at 0.5 Ag À1 .…”

Hausmannite Mn 3 O 4 as a positive active electrode material for rechargeable aqueous Mn‐oxide/Zn batteries

“…Although the nature of the reaction mechanisms involved is still under debate and large‐scale electrodes are yet to be demonstrated, this approach appears to overcome cycling issues related to the alkaline version of the Zn/MnO 2 battery 16‐24 . Among different manganese oxide phases that are reported for near‐neutral batteries, it was discovered that even oxides with lower oxidation states, like Mn 3 O 4 and Mn 2 O 3 , have some activity in this regard 25‐28 . Little attention has been given to the activation mechanism and processes that lead to capacity increase in these phases.…”

“…[16][17][18][19][20][21][22][23][24] Among different manganese oxide phases that are reported for near-neutral batteries, it was discovered that even oxides with lower oxidation states, like Mn 3 O 4 and Mn 2 O 3 , have some activity in this regard. [25][26][27][28] Little attention has been given to the activation mechanism and processes that lead to capacity increase in these phases. The only study in this respect has been that of Zhang et al, 26 which concluded that that Mn 3 O 4 is transforming to the birnessite phase of MnO 2 during charging and after many activation cycles, while discharge capacity originates from zinc intercalation into the birnessite phase.…”

Understanding the Design Principles of Advanced Aqueous Zinc‐Ion Battery Cathodes: From Transport Kinetics to Structural Engineering, and Future Perspectives

“…Notably, such layered host structures can realize an efficient transport kinetics by regulating the interlayer environments. While for nonlayered one, many types of materials also have been reported previously, such as the olivine‐type (LiFePO 4 ) [ 82 ] and spinel‐type (ZnMn 2 O 4 , [ 83 ] Mn 3 O 4 , [ 84 ] and Co 3 O 4 [ 85 ] ) host structures. Among them, the spinel‐type cathode materials usually possess a relatively high operating voltage, but a poor structural stability owing to the thermodynamic instability of phase transition during cycling.…”