title: An in situ SEM-FIB-based method for contrast enhancement and tomographic reconstruction for structural quantification of porous carbon electrodes.
abstract: A new in situ Scanning Electron Microscope-Focused Ion Beam-based method to study porous carbon electrodes involving Pt filling of pores from gaseous precursors has been demonstrated to show drastically improved image contrast between the carbon and porous phases when compared with the Si-resin vacuum-impregnation method. Whereas, the latter method offered up to 20% contrast, the new method offers remarkably higher contrast (42%), which enabled fast semi-automated demarcation of carbon boundaries and subsequent binarization of the images with very high fidelity. Tomographic reconstruction of the porous carbon electrode was then obtained from which several morphological parameters were quantified. The porosity was found to be 72±2%. The axial and radial tortuosites were 1.45±0.04 and 1.43±0.04, respectively. Pore size, which is defined to be the distance from the medial axis of the pore to the nearest solid boundary, was quantified. Average pore size determined from the pore size distribution was 90 nm and the corresponding 1 sigma ranges from 45 to 134 nm. Surface-to-volume ratio of the carbon phase was 46.5 µm(-1). The ratio of total surface area to the total volume of electrode including pores (i.e., specific surface area) was 13 µm(-1).
authors.affiliation: 1Département Science et Analyse des Matériaux (UIS),Centre de Recherche Public - Gabriel Lippmann,41,rue du Brill,L-4422 Belvaux,Luxembourg.
authors.forename: Santhana K
authors.initials: SK
authors.lastname: Eswara-Moorthy
authors.affiliation: 2Central Facility of Electron Microscopy,Group of Electron Microscopy of Material Science,Universität Ulm,89081 Ulm,Germany.
authors.forename: Prasanth
authors.initials: P
authors.lastname: Balasubramanian
authors.affiliation: 2Central Facility of Electron Microscopy,Group of Electron Microscopy of Material Science,Universität Ulm,89081 Ulm,Germany.
authors.forename: Willem
authors.initials: W
authors.lastname: van Mierlo
authors.affiliation: 2Central Facility of Electron Microscopy,Group of Electron Microscopy of Material Science,Universität Ulm,89081 Ulm,Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Bernhard
authors.affiliation: 3Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg,89081 Ulm,Germany.
authors.forename: Mario
authors.initials: M
authors.lastname: Marinaro
authors.affiliation: 3Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg,89081 Ulm,Germany.
authors.forename: Margret
authors.initials: M
authors.lastname: Wohlfahrt-Mehrens
authors.affiliation: 3Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg,89081 Ulm,Germany.
authors.forename: Ludwig
authors.initials: L
authors.lastname: Jörissen
authors.affiliation: 2Central Facility of Electron Microscopy,Group of Electron Microscopy of Material Science,Universität Ulm,89081 Ulm,Germany.
authors.forename: Ute
authors.initials: U
authors.lastname: Kaiser