Expanding Graphite Structure and Surface Morphology

Expanding Graphite is a loose, porous, worm-like material obtained through processes such as intercalation, water washing, drying, and high-temperature expansion from natural flake graphite. It is a new type of granular carbon material with a loose and porous structure. Due to the insertion of intercalation agents, the main body of the graphite gains characteristics such as heat resistance and conductivity, and finds wide applications in fields such as sealing, environmental protection, and flame-retardant fireproof materials. Below, the Baixing Graphite team introduces the structure and surface morphology of expanding graphite:
In recent years, as environmental pollution issues gain increasing public attention, the graphite products prepared by electrochemical methods have garnered attention due to their low environmental impact, low sulfur content, and cost-effectiveness. Moreover, if the electrolyte is not contaminated, it can be reused. The use of a mixture of phosphoric and sulfuric acids as the electrolyte reduces the acid concentration, and the addition of phosphoric acid also enhances the antioxidant properties of expanded graphite. The prepared expanded graphite, when used in thermal insulation and fire-retardant materials, exhibits excellent flame-retardant effects.
Microscopic morphology detection and analysis of flake graphite, expandable graphite, and expanded graphite using SEM. Under high temperatures, the interlayer compounds in expandable graphite will decompose to produce gaseous substances. The gas expansion generates a powerful thrust, causing the graphite to expand along the C-axis and form expanded graphite, which appears worm-like. It can be inferred that due to the expansion, the specific surface area of the expanded graphite is increased, with many pleated pores between the layers. The layered structure is still retained, the van der Waals forces between the layers are disrupted, and the intercalation compounds are expanded sufficiently, resulting in an increased interlayer spacing of the graphite.