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A two-electron transfer mechanism of the Zn-doped δ-MnO 2 cathode toward aqueous Zn-ion batteries with ultrahigh capacity
Neutral aqueous zinc-ion batteries (ZIBs) have attracted considerable attention due to their safe and green features. As one typical cathode, birnessite MnO 2 (δ-MnO 2 ) suffers from low conductivity and structural instability, and its energy storage mechanism is still not well established yet. Here...
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| Published in: | Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2022-03, Vol.10 (12), p.6762-6771 |
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| Main Authors: | , , , , , , , , |
| Format: | Article |
| Language: | English |
| Citations: | Items that this one cites Items that cite this one |
| Online Access: | Get full text |
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| Summary: | Neutral aqueous zinc-ion batteries (ZIBs) have attracted considerable attention due to their safe and green features. As one typical cathode, birnessite MnO
2
(δ-MnO
2
) suffers from low conductivity and structural instability, and its energy storage mechanism is still not well established yet. Herein, we developed a Zn-doped δ-MnO
2
material
via
a facile and effective microwave-assisted method for the cathode in aqueous ZIBs. By incorporating Zn to modify the microstructure and promote reaction kinetics, the Zn-doped δ-MnO
2
electrode demonstrates significantly enhanced electrochemical performance with an ultrahigh reversible capacity of 455 mA h g
−1
and excellent specific energy of 628 W h kg
−1
. In addition, the successive insertion of H
+
and Zn
2+
and deep two-electron transfer routes are revealed systematically by
ex situ
experiments. The two-electron transfer route (Mn
4+
/Mn
3+
and Mn
3+
/Mn
2+
) mechanism of Zn-doped δ-MnO
2
electrodes explains the exceedingly high capacity and opens new opportunities to develop high-energy aqueous ZIBs. |
|---|---|
| ISSN: | 2050-7488 2050-7496 |
| DOI: | 10.1039/D1TA10864F |