Structural improvement of a bio-inspired 3D globular carbon foam by a continuously thermal treatment: A comprehensive study

Abstract

The manufacturing of a 3D interconnected globular carbon foam, called Globugraphite, is based on the replication of the zinc oxide (ZnO) template morphology by carbon with simultaneous removing of the template material in the chemical vapour deposition (CVD -replica CVD (rCVD)) process. The growth mechanism of the presented carbon foam affected the formation of defects at the atomic level which leads in the following to graphitic pieces instead of layers. This substructure influences properties, such as electrical conductivity of the carbon foam negatively. By undergoing a temperature treatment at 1600°C, 1800°C, 2000°C and 2200°C in a protective gas atmosphere the carbon structure heals at the atomic level. The connection of the sp 2 /sp 3 graphitic pieces to graphitic sp 2 layers due to the thermal annealing is analysed via transmission electron microscopy (TEM) observation and Raman spectroscopy. Based on these analysis methods a model of the graphitization progress is created which explains the clearly increase of the electrical conductivity and the oxidation temperature.

Effective Upcycling of Graphite Anode: Healing and Doping Enabled Direct Regeneration

“…43 Interestingly, the B-Graphite was found to be stable up to 700 °C, which is likely due to the stabilizing effect of boron on the surface of graphite. 44,45 In this sample, atmospheric oxygen would preferentially react with boron due to its lower electronegativity when compared to carbon, forming boron oxide. The boron oxide could serve as a physical diffusion barrier, reducing the oxidation rate of graphite.…”