Morphology of nanoporous carbon-binder domains in Li-ion batteries—A FIB-SEM study

Abstract

FIB-SEM tomography is used to reconstruct the carbon binder domain (CBD) of a LiCoO 2 battery cathode (3.9 µm 5 µm 2.3 µm) with contrast enhancement by ZnO infiltration via atomic layer deposition. We calculate the porosity inside the CBD (57.6%), the cluster-size distribution with a peak at 54 nm and the pore-size distribution with a peak at 64 nm. The tortuosities of the pore space (1.6-2.0) and the CBD (2.3-3.5) show a mild anisotropy, which is attributed to the fabrication process. A comparison to a modeled homogenous CBD reveals that clustering in the CBD decreases its electronic conductivity

Numerical reconstruction of microstructure of graphite anode of lithium-ion battery

“…In order to demonstrate the feasibility of ellipsoid-based SAM, the CBD (carbon binder domain) presented by Vierrath et al [43] was reconstructed, and the comparison is given in Table 1. The microstructure of CBD was reconstructed by FIB/SEM tomography and its slight anisotropy was shown.…”

“…We extracted the binarization of CBD section picture as input of the SAM to compute the two-point correlation functions. The carbon particles were assumed to be ellipsoids with polar radius of 15 nm and equatorial radius of 20 nm, according to particle size of 30-40 nm [43]. Then we obtained a slight anisotropy at the reconstructed microstructure by setting particular ellipsoids' rotation angles.…”

“…Morphological and transport parameters of the CBD[43], comparing reconstruction to FIB/SEM tomography and GeoDict ± 0.2 1.7 ± 0.2 1.6 ± 0.2 4.5 ± 0.9 3.1 ± 0.4 3.3 ± 0.4 71 ± 6 81 ± 8 89 ± 8…”

Multiscale Morphological and Electrical Characterization of Charge Transport Limitations to the Power Performance of Positive Electrode Blends for Lithium‐Ion Batteries

“…Novel opportunity for progressing in this direction and explore relationships between electrode architecture and electrochemical performance is implementation of X-ray computed tomography (XRCT) [17][18][19][20][21][22][23][24][25] and focused ion beam in combination with scanning electron microscopy (FIB-SEM) [26][27][28][29][30] techniques to characterize and quantify the 3D architecture of composite electrodes. XRCT is a nondestructive technique that allows probing large volumes covering the entire electrode thickness, which is necessary for reliable analysis.…”

Synchrotron X‐ray Tomographic Study of a Silicon Electrode Before and After Discharge and the Effect of Cavities on Particle Fracturing

“…The nanopores in the CBD cannot be resolved when using synchrotron X‐ray tomography with a pixel size of 438 nm . Therefore, the following CBD denotes a mixture of small, electrolyte‐filled pores and carbon black particles, glued together with binder, which can be reconstructed by using, for example, focussed ion beam (FIB)/SEM …”