X‐ray Nano‐computed Tomography of Electrochemical Conversion in Lithium‐ion Battery

Abstract

Supporting Information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Investigating high-performance sulfur–metal nanocomposites for lithium batteries

“…29 On the other hand, S:Ni 85:15 w/w is formed by bigger, segregated metallic clusters beside micrometric sulfur particles (see Figure 1k and S3b in the Electronic Supplementary Information), thereby suggesting a possible lower rate capability mostly due to increased average electron paths. 48 The nano-CT datasets have been segmented based on the X-ray attenuation by using a grayscale threshold method, 36,37 as shown in the slices of panels h-i and l-m in Figure 1, where exterior, sulfur, tin and nickel are depicted in black, yellow, blue and green, respectively. Hence, segmented volume renderings of a single sulfur-metal agglomerate in panels j and n with the related insets reporting only the metal domains clearly show that tin is mostly embedded within the sulfur phase, while nickel is hosted on the surface.…”

“…Group, FEI Company). The adopted voxel size allowed us the identification of five domains with increasing X-ray attenuation by employing a grayscale threshold method: 36,37 (i) exterior, (ii) carbon/binder/carbon-cloth, (iii) isolated sulfur, (iv) sulfur-metal nanoparticle intimate mixture, (v) isolated metal domain. Binary datasets were produced after segmentation to evaluate the particle size distribution of the domain formed by isolated sulfur and intimate mixture of sulfur and metallic nanoparticles.…”

“…Furthermore, panels g-n reveal a rather different morphology of the sulfurmetal agglomerates at the nanoscale, suggesting a more intimate mixing between the two phases for S:Sn 85:15 w/w with respect to S:Ni 85:15 w/w. TEM and X-ray nano-CT may provide qualitative information on the sample composition as the density of the various phases forming the composite are directly reflected into the attenuation coefficient for the incident beam 37. Accordingly, the relevant difference of sulfur and metal densities (2.07, 7.31 and 8.9 g/cm 3 at 25 °C for S, Sn and Ni, respectively) 49 allows unambiguous phase identification: metal particles/agglomerates are therefore observed in the TEM images (Figure1g, k) and X-ray nano-CT reconstructions (Figure1h, l and…”

“…Crystal structure of the nanocomposites was studied by X-ray diffraction (XRD) through a unsharp masking filters, segmented, and imaged through Avizo 2019.2 (Visualization Sciences Group, FEI Company). Three domains with increasing X-ray attenuation were identified by employing a grayscale threshold method:36,37 (i) exterior, (ii) sulfur, (iii) metal…”

Electrochemical behavior of nanostructured NiO@C anode in a lithium-ion battery using LiNi⅓Co⅓Mn⅓O2 cathode

“…Transition metal sulfides have similar characteristics as conversion anodes in terms of capacity, however they suffer from the typical drawbacks of conversion electrodes [12]. Hence, in spite of the attractive capacity, the conversion reaction is characterized by massive microstructural rearrangements [13] mostly leading to substantial volume changes of the electrode material and large voltage hysteresis, which may adversely affect the reversibility and efficiency of the process [9]. Furthermore, they typically show a higher working voltage than graphite and Li-alloying anodes [9,14].…”