Table 1 Quantified morphological data extracted from the binarized reconstructed volumes obtained with HAADF-STEM electron tomography.

From: Three-dimensional analysis of Nafion layers in fuel cell electrodes

Sample

Volume fraction (%)

Surface coverage (%)

Average layer thickness (nm)

Sample 1

 Nafion/CB=0.5 w/w

20.3±2.0

79.5±2.3

7.2±2.1

Sample 2

 Nafion/CB=0.2 w/w

13.6±0.2

49.9±1.2

7.6±2.2

  1. CB, carbon black; HAADF-STEM, high-angle annular dark-field scanning transmission electron microscope.
  2. The error margins derive from using different smoothing procedures in the binarization process of the 3D-reconstructed volumes, see Supplementary Fig. 2. The CB surface coverage δ is calculated with the following formula: δ (%)=(area of the ionomer layer/surface of CB nanoparticles) × 100.
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