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Probing three-dimensional sodiation-desodiation equilibrium in sodium-ion batteries by in situ hard X-ray nanotomography.

Wang J, Eng C, Chen-Wiegart YC, Wang J - Nat Commun (2015)

Bottom Line: Efforts to relieve this problem are reliant on the understanding of electrochemical and structural degradation.We find an unusual (de)sodiation equilibrium during multi-electrochemical cycles.The superior structural reversibility during 10 electrochemical cycles and the significantly different morphological change features from comparable lithium-ion systems suggest untapped potential in sodium-ion batteries.

View Article: PubMed Central - PubMed

Affiliation: National Synchrotron Light Source II, Brookhaven National Laboratory, Building 743 Ring Road, Upton, New York 11973, USA.

ABSTRACT
Materials degradation-the main limiting factor for widespread application of alloy anodes in battery systems-was assumed to be worse in sodium alloys than in lithium analogues due to the larger sodium-ion radius. Efforts to relieve this problem are reliant on the understanding of electrochemical and structural degradation. Here we track three-dimensional structural and chemical evolution of tin anodes in sodium-ion batteries with in situ synchrotron hard X-ray nanotomography. We find an unusual (de)sodiation equilibrium during multi-electrochemical cycles. The superior structural reversibility during 10 electrochemical cycles and the significantly different morphological change features from comparable lithium-ion systems suggest untapped potential in sodium-ion batteries. These findings differ from the conventional thought that sodium ions always lead to more severe fractures in the electrode than lithium ions, which could have impact in advancing development of sodium-ion batteries.

No MeSH data available.


Related in: MedlinePlus

3D view of microstructural equilibrium in NIB.(a) microstructural reversibility during 10 sodiation–desodiation cycles; The overlapped images of (b) pristine/second desodiated, (c) pristine/tenth sodiated and (d) second sodiated/tenth desodiated. The contrast of the overlapping colors (b–d) are adjusted for better visualization. A microstructural equilibrium reaches since the second sodiation–desodiation process. (e) The electrochemical cycle performance; (f) volume and surface area change during the electrochemical cycles; (g) quantitative specific area change during the electrochemical cycles. Scale bar, 10 μm.
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f4: 3D view of microstructural equilibrium in NIB.(a) microstructural reversibility during 10 sodiation–desodiation cycles; The overlapped images of (b) pristine/second desodiated, (c) pristine/tenth sodiated and (d) second sodiated/tenth desodiated. The contrast of the overlapping colors (b–d) are adjusted for better visualization. A microstructural equilibrium reaches since the second sodiation–desodiation process. (e) The electrochemical cycle performance; (f) volume and surface area change during the electrochemical cycles; (g) quantitative specific area change during the electrochemical cycles. Scale bar, 10 μm.

Mentions: In spite of significant morphological change during the first cycle, Sn particles seem to show excellent microstructural stability during the following cycles (Fig. 4a–d). The high mechanical stability is well consistent with excellent electrochemical reversibility (Fig. 4e), which is further supported by the 3D quantitative analysis (Fig. 4f,g). The volume expansion is ∼326% after the first sodiation, which will lead to an increase of surface area by a factor of ∼2.19 if there is no morphological degradation. But the overall surface area undergoes five times increase, which suggests that significant microstructural degradation occurred resulting in the formation of many small objects during the first sodiation. The specific surface area (defined as the surface area per unit volume of materials), a typical structural parameter to characterize material's pulverization, also reveals the same trend. Interestingly, since the second cycle, both volume and surface area undergo reversible expansion and shrinkage, and the specific surface area keeps stable, indicating that the microstructure reaches equilibrium.


Probing three-dimensional sodiation-desodiation equilibrium in sodium-ion batteries by in situ hard X-ray nanotomography.

Wang J, Eng C, Chen-Wiegart YC, Wang J - Nat Commun (2015)

3D view of microstructural equilibrium in NIB.(a) microstructural reversibility during 10 sodiation–desodiation cycles; The overlapped images of (b) pristine/second desodiated, (c) pristine/tenth sodiated and (d) second sodiated/tenth desodiated. The contrast of the overlapping colors (b–d) are adjusted for better visualization. A microstructural equilibrium reaches since the second sodiation–desodiation process. (e) The electrochemical cycle performance; (f) volume and surface area change during the electrochemical cycles; (g) quantitative specific area change during the electrochemical cycles. Scale bar, 10 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4491187&req=5

f4: 3D view of microstructural equilibrium in NIB.(a) microstructural reversibility during 10 sodiation–desodiation cycles; The overlapped images of (b) pristine/second desodiated, (c) pristine/tenth sodiated and (d) second sodiated/tenth desodiated. The contrast of the overlapping colors (b–d) are adjusted for better visualization. A microstructural equilibrium reaches since the second sodiation–desodiation process. (e) The electrochemical cycle performance; (f) volume and surface area change during the electrochemical cycles; (g) quantitative specific area change during the electrochemical cycles. Scale bar, 10 μm.
Mentions: In spite of significant morphological change during the first cycle, Sn particles seem to show excellent microstructural stability during the following cycles (Fig. 4a–d). The high mechanical stability is well consistent with excellent electrochemical reversibility (Fig. 4e), which is further supported by the 3D quantitative analysis (Fig. 4f,g). The volume expansion is ∼326% after the first sodiation, which will lead to an increase of surface area by a factor of ∼2.19 if there is no morphological degradation. But the overall surface area undergoes five times increase, which suggests that significant microstructural degradation occurred resulting in the formation of many small objects during the first sodiation. The specific surface area (defined as the surface area per unit volume of materials), a typical structural parameter to characterize material's pulverization, also reveals the same trend. Interestingly, since the second cycle, both volume and surface area undergo reversible expansion and shrinkage, and the specific surface area keeps stable, indicating that the microstructure reaches equilibrium.

Bottom Line: Efforts to relieve this problem are reliant on the understanding of electrochemical and structural degradation.We find an unusual (de)sodiation equilibrium during multi-electrochemical cycles.The superior structural reversibility during 10 electrochemical cycles and the significantly different morphological change features from comparable lithium-ion systems suggest untapped potential in sodium-ion batteries.

View Article: PubMed Central - PubMed

Affiliation: National Synchrotron Light Source II, Brookhaven National Laboratory, Building 743 Ring Road, Upton, New York 11973, USA.

ABSTRACT
Materials degradation-the main limiting factor for widespread application of alloy anodes in battery systems-was assumed to be worse in sodium alloys than in lithium analogues due to the larger sodium-ion radius. Efforts to relieve this problem are reliant on the understanding of electrochemical and structural degradation. Here we track three-dimensional structural and chemical evolution of tin anodes in sodium-ion batteries with in situ synchrotron hard X-ray nanotomography. We find an unusual (de)sodiation equilibrium during multi-electrochemical cycles. The superior structural reversibility during 10 electrochemical cycles and the significantly different morphological change features from comparable lithium-ion systems suggest untapped potential in sodium-ion batteries. These findings differ from the conventional thought that sodium ions always lead to more severe fractures in the electrode than lithium ions, which could have impact in advancing development of sodium-ion batteries.

No MeSH data available.


Related in: MedlinePlus