Open AccessStudy of the electrical conductivity of biobased carbonaceous powder materials under moderate pressure for the application as electrode materials in energy storage technologies
Author(s) -
Hoffmann Viola,
Rodriguez Correa Catalina,
Sautter Dennis,
Maringolo Emilio,
Kruse Andrea
Publication year - 2019
Publication title -
gcb bioenergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.378
H-Index - 63
eISSN - 1757-1707
pISSN - 1757-1693
DOI - 10.1111/gcbb.12545
Subject(s) - materials science , carbonization , corncob , pyrolysis , biochar , oxide , chemical engineering , electrode , metal , electrical resistivity and conductivity , composite material , chemistry , metallurgy , organic chemistry , electrical engineering , scanning electron microscope , raw material , engineering
Abstract This study focusses on the assessment of the electrical conductivity ( EC ) of biobased electrode materials for the application in energy storage devices and presents a simple and reproducible method to measure the EC of carbonaceous powders under moderate pressure (10–50 N). Based on the pyrolysis of corncob at three different temperatures (600, 800, and 900°C) and further treatments of the biochar obtained at 600°C, 11 different carbonaceous powder materials were produced including biochars, activated carbons, and composites. Composite materials were obtained by adding either metal oxide (RuO 2 or Fe 3 O 4 ) in different proportions or additives which are commonly used in electrode production (5 wt% binder and 15 wt% conductive additive). Furthermore, one physically activated commercial AC based on peat with a known EC of 33 S/m was treated with additives and used as a reference. For all materials, an increase of applied pressure resulted in higher EC values due to closer particle contact. The comparison of two methods (with and without preload) showed that a prepelletization of the samples is not necessary to obtain reliable results. By analyzing the obtained EC values while taking mechanical and physicochemical properties into account, it could be shown that a high carbonization temperature and high specific surface area favor the increase of EC . Furthermore, certain proportions of metal oxides lead to an improvement of EC (40 wt% RuO 2 , 10 wt% Fe 3 O 4 ), while the treatment with additives leads to a decrease of EC . The EC values among all samples varied between 0.8 S/m (biochar) and 408 S/m ( AC /RuO 2 composite) at the highest pressure level (637 kPa). Thus, promising biobased electrode materials for environmentally friendly energy storage technologies are presented with the aim of contributing to the establishment of a biobased resource and product platform for bioeconomy.