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- Dwibedi, Debasmita, et al.
(författare)
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Na2.44Mn1.79(SO4)(3) : a new member of the alluaudite family of insertion compounds for sodium ion batteries
- 2015
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 3:36, s. 18564-18571
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Tidskriftsartikel (refereegranskat)abstract
- Sodium-ion batteries have been extensively pursued as economic alternatives to lithium-ion batteries. Investigating the polyanion chemistry, alluaudite structured Na2Fe2II(SO4)(3) has been recently discovered as a 3.8 V positive electrode material (Barpanda et al., Nature Commun., 5: 4358, 2014). Registering the highest ever Fe-III/Fe-II redox potential (vs. Na/Na+) and formidable energy density, it has opened up a new polyanion family for sodium batteries. Exploring the alluaudite family, here we report isotypical Na2+2xMn2-xII(SO4)(3) (x = 0.22) as a novel high-voltage cathode material for the first time. Following low-temperature (ca. 350 degrees C) solid-state synthesis, the structure of this new alluaudite compound has been solved adopting a monoclinic framework (s.g. C2/c) showing antiferromagnetic ordering at 3.4 K. Synergising experimental and ab initio DFT investigation, Na2+2xMn2-xII(SO4)(3) has been found to be a potential high-voltage (ca. 4.4 V) cathode material for sodium batteries.
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| 3. |
- Singh, Deobrat, et al.
(författare)
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Eldfellite NaV(SO4)2 as a versatile cathode insertion host for Li-ion and Na-ion batteries
- 2022
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 11:8, s. 3975-3986
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Tidskriftsartikel (refereegranskat)abstract
- In search of high energy density cathode materials, the eldfellite mineral-type NaVIII(SO4)2 compound has been theoretically predicted to be a promising cathode insertion host for sodium-ion batteries. Synergizing computational and experimental investigations, the current work introduces NaVIII(SO4)2 as a novel versatile cathode for Li-ion and Na-ion batteries. Prepared by a low temperature sol-gel synthesis route, the eldfellite NaV(SO4)2 cathode exhibited an initial capacity approaching ∼79% (vs. Li+/Li) and ∼69% (vs. Na+/Na) of the theoretical capacity (1e− ≅ 101 mA h g−1) involving the V3+/V2+ redox potential centered at 2.57 V and 2.28 V, respectively. The bond valence site energy (BVSE) approach and DFT-based calculations were used to gain mechanistic insight into alkali ion migration and probe the redox center during (de)insertion of Li+/Na+ ions. Post-mortem and electrochemical titration tools revealed the occurrence of a single-phase (solid-solution) redox mechanism during reversible Li+/Na+ (de)insertion into NaVIII(SO4)2. With the multivalent vanadium redox center, eldfellite NaVIII(SO4)2 forms a new cathode insertion host for Li/Na-ion batteries with potential two-electron uptake.
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