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Visualizing nanoscale 3D compositional fluctuation of lithium in advanced lithium-ion battery cathodes.

Devaraj A, Gu M, Colby R, Yan P, Wang CM, Zheng JM, Xiao J, Genc A, Zhang JG, Belharouak I, Wang D, Amine K, Thevuthasan S - Nat Commun (2015)

Bottom Line: Cycled material has an overall loss of Li in addition to Ni-, Mn- and Li-rich regions.Spinel LiNi0.5Mn1.5O4 is shown to have a uniform distribution of all cations.APT results were compared to energy dispersive spectroscopy mapping with a scanning transmission electron microscope to confirm the transition metal cation distribution.

View Article: PubMed Central - PubMed

Affiliation: Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.

ABSTRACT
The distribution of cations in Li-ion battery cathodes as a function of cycling is a pivotal characteristic of battery performance. The transition metal cation distribution has been shown to affect cathode performance; however, Li is notoriously challenging to characterize with typical imaging techniques. Here laser-assisted atom probe tomography (APT) is used to map the three-dimensional distribution of Li at a sub-nanometre spatial resolution and correlate it with the distribution of the transition metal cations (M) and the oxygen. As-fabricated layered Li1.2Ni0.2Mn0.6O2 is shown to have Li-rich Li2MO3 phase regions and Li-depleted Li(Ni0.5Mn0.5)O2 regions. Cycled material has an overall loss of Li in addition to Ni-, Mn- and Li-rich regions. Spinel LiNi0.5Mn1.5O4 is shown to have a uniform distribution of all cations. APT results were compared to energy dispersive spectroscopy mapping with a scanning transmission electron microscope to confirm the transition metal cation distribution.

No MeSH data available.


Related in: MedlinePlus

Statistical analysis of element segregation in spinel-LNMO:Frequency distributions of Li, Ni, Mn and O in spinel-LNMO with corresponding Pearson coefficients (μ). (a–d) showing distributions rather close to uniform for Li, Ni, Mn, and O.
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f5: Statistical analysis of element segregation in spinel-LNMO:Frequency distributions of Li, Ni, Mn and O in spinel-LNMO with corresponding Pearson coefficients (μ). (a–d) showing distributions rather close to uniform for Li, Ni, Mn, and O.

Mentions: Frequency distribution analysis of the APT results from spinel LNMO was conducted to quantify the uniformity of the distribution of each element. Figure 5a–d shows the observed frequency distributions of Li, Ni, Mn and O compared with a binomial distribution. It is clear that spinel-LNMO has a more uniform distribution compared to the as-fabricated layered-LNMO shown in Fig. 2. The Pearson coefficients estimated from the 200 atom bin size frequency distribution analysis for Li, Ni, Mn and O were 0.109, 0.047, 0.073 and 0.106 respectively (shown as inset in Fig. 5), all indicating a very close to uniform distribution. The Pearson coefficient estimated for all the molecular species were also well below 0.1. A Pearson coefficient value close to 0 is indicative of a uniform distribution of elements5255. The P values estimated at a 95% confidence interval for Li and O was observed to be below 0.001 and the P value for Mn and Ni were 0.095 and 0.568. These P values in combination with the Pearson coefficient values when compared with layered-LNMO results indicate that there is only a minor deviation from random distribution for Li and O, but Ni and Mn are distributed rather uniformly in the spinel-LNMO APT result.


Visualizing nanoscale 3D compositional fluctuation of lithium in advanced lithium-ion battery cathodes.

Devaraj A, Gu M, Colby R, Yan P, Wang CM, Zheng JM, Xiao J, Genc A, Zhang JG, Belharouak I, Wang D, Amine K, Thevuthasan S - Nat Commun (2015)

Statistical analysis of element segregation in spinel-LNMO:Frequency distributions of Li, Ni, Mn and O in spinel-LNMO with corresponding Pearson coefficients (μ). (a–d) showing distributions rather close to uniform for Li, Ni, Mn, and O.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4557343&req=5

f5: Statistical analysis of element segregation in spinel-LNMO:Frequency distributions of Li, Ni, Mn and O in spinel-LNMO with corresponding Pearson coefficients (μ). (a–d) showing distributions rather close to uniform for Li, Ni, Mn, and O.
Mentions: Frequency distribution analysis of the APT results from spinel LNMO was conducted to quantify the uniformity of the distribution of each element. Figure 5a–d shows the observed frequency distributions of Li, Ni, Mn and O compared with a binomial distribution. It is clear that spinel-LNMO has a more uniform distribution compared to the as-fabricated layered-LNMO shown in Fig. 2. The Pearson coefficients estimated from the 200 atom bin size frequency distribution analysis for Li, Ni, Mn and O were 0.109, 0.047, 0.073 and 0.106 respectively (shown as inset in Fig. 5), all indicating a very close to uniform distribution. The Pearson coefficient estimated for all the molecular species were also well below 0.1. A Pearson coefficient value close to 0 is indicative of a uniform distribution of elements5255. The P values estimated at a 95% confidence interval for Li and O was observed to be below 0.001 and the P value for Mn and Ni were 0.095 and 0.568. These P values in combination with the Pearson coefficient values when compared with layered-LNMO results indicate that there is only a minor deviation from random distribution for Li and O, but Ni and Mn are distributed rather uniformly in the spinel-LNMO APT result.

Bottom Line: Cycled material has an overall loss of Li in addition to Ni-, Mn- and Li-rich regions.Spinel LiNi0.5Mn1.5O4 is shown to have a uniform distribution of all cations.APT results were compared to energy dispersive spectroscopy mapping with a scanning transmission electron microscope to confirm the transition metal cation distribution.

View Article: PubMed Central - PubMed

Affiliation: Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, USA.

ABSTRACT
The distribution of cations in Li-ion battery cathodes as a function of cycling is a pivotal characteristic of battery performance. The transition metal cation distribution has been shown to affect cathode performance; however, Li is notoriously challenging to characterize with typical imaging techniques. Here laser-assisted atom probe tomography (APT) is used to map the three-dimensional distribution of Li at a sub-nanometre spatial resolution and correlate it with the distribution of the transition metal cations (M) and the oxygen. As-fabricated layered Li1.2Ni0.2Mn0.6O2 is shown to have Li-rich Li2MO3 phase regions and Li-depleted Li(Ni0.5Mn0.5)O2 regions. Cycled material has an overall loss of Li in addition to Ni-, Mn- and Li-rich regions. Spinel LiNi0.5Mn1.5O4 is shown to have a uniform distribution of all cations. APT results were compared to energy dispersive spectroscopy mapping with a scanning transmission electron microscope to confirm the transition metal cation distribution.

No MeSH data available.


Related in: MedlinePlus