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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

Visualization of three-dimensional (3D) microstructural evolution in NIB.(a) Experimental setup and electrochemical cells. (b) 3D morphological change of Sn particles during the first sodiation–desodiation cycle. The colours in b represent the attenuation coefficient variation within the reconstructed images. Overlapped 3D views of Sn particles at different electrochemical stages: (c) pristine/sodiated, (d) sodiated/desodiated and (e) pristine/desodiated. The contrast of the overlapping colors (c–e) are adjusted for better visualization. (f) Normalized X-ray attenuation coefficient histogram during the first electrochemical cycle. (g) Schematic illustration showing the two-step sodiation process, which is supported by the cross-section images of selected particle shown above (grey), in which the initial sodiation process leads to negligible volume change. (h)The histogram information of attenuation coefficient change, which is correlated the above 3D morphological change to chemical information change. Scale bar, 10 μm.
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f1: Visualization of three-dimensional (3D) microstructural evolution in NIB.(a) Experimental setup and electrochemical cells. (b) 3D morphological change of Sn particles during the first sodiation–desodiation cycle. The colours in b represent the attenuation coefficient variation within the reconstructed images. Overlapped 3D views of Sn particles at different electrochemical stages: (c) pristine/sodiated, (d) sodiated/desodiated and (e) pristine/desodiated. The contrast of the overlapping colors (c–e) are adjusted for better visualization. (f) Normalized X-ray attenuation coefficient histogram during the first electrochemical cycle. (g) Schematic illustration showing the two-step sodiation process, which is supported by the cross-section images of selected particle shown above (grey), in which the initial sodiation process leads to negligible volume change. (h)The histogram information of attenuation coefficient change, which is correlated the above 3D morphological change to chemical information change. Scale bar, 10 μm.

Mentions: The in situ experimental setup and 3D structural evolution of Sn particles during the first electrochemical cycle are represented in Fig. 1a–e (Supplementary Figs 1 and 2, Supplementary Movies 1 and 2). At the beginning of the sodiation process, Sn particles undergo negligible volume expansion and the overall structures remain unchanged. With further sodiation, severe morphological expansion occurs and many cracks were observed (indicated by white arrows; Supplementary Figs 3 and 4). During the following desodiation process, the extraction of Na ions leads to the volume shrinkage, but surprisingly, no obvious pulverization or structural failure occurs. This modest structural damage during Na-ion extraction is remarkably different from the analogous LIB in which the Li-ion extraction rather than the insertion process evokes severe structural degradation and the formation of many pores17.


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)

Visualization of three-dimensional (3D) microstructural evolution in NIB.(a) Experimental setup and electrochemical cells. (b) 3D morphological change of Sn particles during the first sodiation–desodiation cycle. The colours in b represent the attenuation coefficient variation within the reconstructed images. Overlapped 3D views of Sn particles at different electrochemical stages: (c) pristine/sodiated, (d) sodiated/desodiated and (e) pristine/desodiated. The contrast of the overlapping colors (c–e) are adjusted for better visualization. (f) Normalized X-ray attenuation coefficient histogram during the first electrochemical cycle. (g) Schematic illustration showing the two-step sodiation process, which is supported by the cross-section images of selected particle shown above (grey), in which the initial sodiation process leads to negligible volume change. (h)The histogram information of attenuation coefficient change, which is correlated the above 3D morphological change to chemical information change. Scale bar, 10 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f1: Visualization of three-dimensional (3D) microstructural evolution in NIB.(a) Experimental setup and electrochemical cells. (b) 3D morphological change of Sn particles during the first sodiation–desodiation cycle. The colours in b represent the attenuation coefficient variation within the reconstructed images. Overlapped 3D views of Sn particles at different electrochemical stages: (c) pristine/sodiated, (d) sodiated/desodiated and (e) pristine/desodiated. The contrast of the overlapping colors (c–e) are adjusted for better visualization. (f) Normalized X-ray attenuation coefficient histogram during the first electrochemical cycle. (g) Schematic illustration showing the two-step sodiation process, which is supported by the cross-section images of selected particle shown above (grey), in which the initial sodiation process leads to negligible volume change. (h)The histogram information of attenuation coefficient change, which is correlated the above 3D morphological change to chemical information change. Scale bar, 10 μm.
Mentions: The in situ experimental setup and 3D structural evolution of Sn particles during the first electrochemical cycle are represented in Fig. 1a–e (Supplementary Figs 1 and 2, Supplementary Movies 1 and 2). At the beginning of the sodiation process, Sn particles undergo negligible volume expansion and the overall structures remain unchanged. With further sodiation, severe morphological expansion occurs and many cracks were observed (indicated by white arrows; Supplementary Figs 3 and 4). During the following desodiation process, the extraction of Na ions leads to the volume shrinkage, but surprisingly, no obvious pulverization or structural failure occurs. This modest structural damage during Na-ion extraction is remarkably different from the analogous LIB in which the Li-ion extraction rather than the insertion process evokes severe structural degradation and the formation of many pores17.

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