Rechargeable aqueous batteries with Zn2+as a working‐ion are promising candidates for grid‐scale energy storage because of their intrinsic safety, low‐cost, and high energy‐intensity. However, suitable cathode materials with excellent Zn2+‐storage cyclability must be found in order for Zinc‐ion batteries (ZIBs) to find practical applications. Herein, NaCa0.6V6O16·3H2O (NaCaVO) barnesite nanobelts are reported as an ultra‐stable ZIB cathode material. The original capacity reaches 347 mAh g−1at 0.1 A g−1, and the capacity retention rate is 94% after 2000 cycles at 2 A g−1and 83% after 10 000 cycles at 5 A g−1, respectively. Through a combined theoretical and experimental approach, it is discovered that the unique V3O8layered structure in NaCaVO is energetically favorable for Zn2+diffusion and the structural water situated between V3O8layers promotes a fast charge‐transfer and bulk migration of Zn2+by enlarging gallery spacing and providing more Zn‐ion storage sites. It is also found that Na+and Ca2+alternately suited in V3O8layers are the essential stabilizers for the layered structure, which play a crucial role in retaining long‐term cycling stability.
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Aqueous zinc‐ion batteries are promising alternatives to lithium‐ion batteries due to their cost‐effectiveness and improved safety. However, several challenges, including corrosion, dendrites, and water decomposition at the Zn anode, hinder their performance. Herein, an approach is proposed, that deviates from the conventional design by adding water into a propylene carbonate‐based organic electrolyte to prepare a non‐flammable “water‐in‐organic” electrolyte. The chaotropic salt Zn(ClO4)2exploits the Hofmeister effect to promote the miscibility of immiscible liquid phases. Interactions between propylene carbonate and water restrict water activity and mitigate unfavorable reactions. This electrolyte facilitates preferential Zn (002) deposition and the formation of solid electrolyte interphase. Consequently, the “water‐in‐organic” electrolyte achieves a 99.5% Coulombic efficiency at 1 mA cm−2over 1000 cycles in Zn/Cu cells, and constant cycling over 1000 h in Zn/Zn symmetric cells. A Na0.33V2O5/Zn battery exhibits impressive cycling stability with a capacity of 175 mAh g−1for 800 cycles at 2 A g−1. Additionally, this electrolyte enables sustainable cycling across a wide temperature range from −20 to 50 °C. The design of a “water‐in‐organic” electrolyte employing a chaotropic salt presents a potential strategy for high‐performance electrolytes in zinc‐ion batteries with a large stability window and a wide temperature range.
more » « less- Award ID(s):
- 1720595
- PAR ID:
- 10509911
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 34
- Issue:
- 9
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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