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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

Statistical analysis of morphological complexity degree.(a) 3D morphologies of the sodiated electrode and selected three particles with different size and fracture. (b) Size-dependent morphological complexity for the pristine and sodiated samples. (c) An enlarged plot showing three different fracture zone. (d) A schematic illustration gives the two critical sizes for Sn fracture in NIB.
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f3: Statistical analysis of morphological complexity degree.(a) 3D morphologies of the sodiated electrode and selected three particles with different size and fracture. (b) Size-dependent morphological complexity for the pristine and sodiated samples. (c) An enlarged plot showing three different fracture zone. (d) A schematic illustration gives the two critical sizes for Sn fracture in NIB.

Mentions: To quantify the structural failure in NIB, statistical analysis of morphological complexity degree were performed on these individual particles. The 3D morphologies of the entire electrode and several representative particles (small, medium and large sized) were shown in Fig. 3a. Here the complexity degree (a unit-less parameter, η) is measured by the ratio of the radius Rs (the radius calculated from the actual surface area) to the radius Rv (the radius from the volume V; Supplementary Note 4). If an ideally ball-shaped particle (most of pristine Sn particles are ball-shaped, as shown in the mosaic image) is robust enough to survive the big volume expansion (no cracks, fracture or pulverization) after Na ions insertion/extraction, the η-value should be around 1. The higher the value is, the more complexity has occurred. This particle complexity can refer to the microstructural degradation in pores, cracks, fracture and pulverization. The similar parameter was also used to quantify the microstructural change for cathode battery materials that generally low-morphological change exist32. The statistical result in Fig. 3b shows an obvious size-dependent complexity for Sn particles, and the zoom-in plot (Fig. 3c) gives three different complexity zones, in which low complexity occurs above 0.5 μm zone and high complexity happens over 1.6 μm zone. Below 0.5 μm, Sn particles show negligible structural degradation and keep the microstructural integrity. Therefore, the two critical sizes (0.5 μm for low complexity and 1.6 μm for high complexity, Fig. 3d) provide new insights into the failure mechanism and a basis for further engineering battery materials in NIB.


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)

Statistical analysis of morphological complexity degree.(a) 3D morphologies of the sodiated electrode and selected three particles with different size and fracture. (b) Size-dependent morphological complexity for the pristine and sodiated samples. (c) An enlarged plot showing three different fracture zone. (d) A schematic illustration gives the two critical sizes for Sn fracture in NIB.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f3: Statistical analysis of morphological complexity degree.(a) 3D morphologies of the sodiated electrode and selected three particles with different size and fracture. (b) Size-dependent morphological complexity for the pristine and sodiated samples. (c) An enlarged plot showing three different fracture zone. (d) A schematic illustration gives the two critical sizes for Sn fracture in NIB.
Mentions: To quantify the structural failure in NIB, statistical analysis of morphological complexity degree were performed on these individual particles. The 3D morphologies of the entire electrode and several representative particles (small, medium and large sized) were shown in Fig. 3a. Here the complexity degree (a unit-less parameter, η) is measured by the ratio of the radius Rs (the radius calculated from the actual surface area) to the radius Rv (the radius from the volume V; Supplementary Note 4). If an ideally ball-shaped particle (most of pristine Sn particles are ball-shaped, as shown in the mosaic image) is robust enough to survive the big volume expansion (no cracks, fracture or pulverization) after Na ions insertion/extraction, the η-value should be around 1. The higher the value is, the more complexity has occurred. This particle complexity can refer to the microstructural degradation in pores, cracks, fracture and pulverization. The similar parameter was also used to quantify the microstructural change for cathode battery materials that generally low-morphological change exist32. The statistical result in Fig. 3b shows an obvious size-dependent complexity for Sn particles, and the zoom-in plot (Fig. 3c) gives three different complexity zones, in which low complexity occurs above 0.5 μm zone and high complexity happens over 1.6 μm zone. Below 0.5 μm, Sn particles show negligible structural degradation and keep the microstructural integrity. Therefore, the two critical sizes (0.5 μm for low complexity and 1.6 μm for high complexity, Fig. 3d) provide new insights into the failure mechanism and a basis for further engineering battery materials in NIB.

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