Data on the theoretical X-Ray attenuation and transmissions for lithium-ion battery cathodes

This article reports the data required for planning attenuation-based X-ray characterisation e.g. X-ray computed tomography (CT), of lithium-ion (Li-ion) battery cathodes. The data reported here is to accompany a co-submitted manuscript (10.1016/j.matdes.2020.108585 [1]) which compares two well-known X-ray attenuation data sources: Henke et al. and Hubbell et al., and applies methodology reported by Reiter et al. to extend this data towards the practical characterisation of prominent cathode materials. This data may be used to extend beyond the analysis reported in the accompanying manuscript, and may aid in the applications for other materials, not limited to Li-ion batteries.


Specifications table
Materials Science Specific subject area X-ray properties of prominent Li-ion battery cathode materials, for optimising X-ray computed tomography characterisation. Type of data 38 Tables  How data were acquired No experimental data was collected for this work, all data reported is calculated using spreadsheets generated in Excel 2016 software from spectroscopy and modelling data from published sources [2] and [3] . Data format Computed from analysed from raw reference data. Parameters for data collection All parameters and equations used for the calculations that generated this data are in Section 2.1 . Description for data collection The methodology for the calculations that were employed in order to obtain this data is outlined within the complimentary article and within Section 2 of this article. Data

Value of the Data
• This data allows for the optimisation of X-ray CT imaging for Li-ion cathodes • These tables will benefit all who investigate structures using attenuation-based X-ray imaging • This may also be used to calculated X-ray properties for analogous chemistries Table 1 displays literature references for the crystallographic densities and chemical compositions for NMC111, 532, 622 and 811. Tables 2-9 report the first set of data calculated from the information published by Hubbell and Seltzer [2] , followed by Tables 10-19 using information published by Henke et al. [3] . It should be noted that, for direct comparison, the same literature references for the crystallographic densities of the various NMC chemistries were used for both sets of calculations [4][5][6][7] . Tables 20-35 report the theoretical X-ray transmissions for the various cathode materials for numerous experimental scenarios, e.g. incident beam energies and sample thickness. Using derivations outlined by Reiter et al. [8] , the optimal thicknesses for NMC for beam energies from 1 -100 keV are reported in Tables 36 and 37 . And finally, the applicability of these values for operational experiments is considered by examining the influence of lithiaiton upon the aforementioned metrics in Table 38 . For a full analysis and discussion see the related research article [1] .

Essential X-ray equations
No raw data was acquired for this work. All data was calculated from the references. The following set of equations describe all calculations within this work.

Table 22
Theoretical X-ray transmission for NMC 111 for thicknesses of 10 -100 μm and incident beam energies of 1 -10 keV, presented as a percentage to 2 dp.

Table 37
Theoretical thicknesses for optimal contrast-to-noise ratio for various NMC chemistries and incident beam energies of 10 -100 keV, presented in μm to 2 d.p.

Table 38
The influence of lithiation state upon the X-ray attenuation properties of NMC811 for three incident beam energies: 1, 10 and 100 keV, presented are X-ray mass attenuation coefficients in cm 2 g −1 (to 2 d.p.).
Calculating X-ray transmission from the X-ray linear attenuation coefficient or the X-ray attenuation length ( Eq. (4) ).

X-Ray attenuation data calculated from Hubbell
These tables report data produced from work by Hubbell and Seltzer [2] .

X-Ray attenuation data calculated from Henke
These tables report data produced from work by Henke et al. [3] . The same literature references for the crystallographic densities of the various NMC chemistries were used for both the attenuation calculations based upon Hubbell and Henke [4][5][6][7] .

X-Ray transmissions for NMC111
Firstly transmission values for small samples. Secondly transmission values for large samples.

X-Ray transmissions for NMC532
Firstly transmission values for small samples. Secondly transmission values for large samples.

X-Ray transmissions for NMC622
Firstly transmission values for small samples. Secondly transmission values for large samples.

X-Ray transmissions for NMC811
Firstly transmission values for small samples. Secondly transmission values for large samples.

Theoretical NMC thickness for optimum image contrast
Using derivations outlined by Reiter et al. [8] , the theoretical thickness for optimum image contrast can be calculated using Eq. (5) : firstly, for low energies ( Table 36 ), and secondly, for high energies ( Table 37 ).

Theoretical influence of electrode lithiation
All calculations thus far have reported results based upon fully lithiated material, because the influence of lithiation is assumed negligible with comparison to variations in the incident beam energy or chemical composition. In order to demonstrate the validity of this assumption, Table 38 reports the theoretical variation in X-ray mass attenuation coefficient with state of charge (quantified by the value of x within Li 1-x Ni 0.8 Mn 0.1 Co 0.1 O 2 ) for three incident beam energies: 1, 10, 100 keV.