Polypyrrole/montmorillonite and polypyrrole/ghassoul intercalates as a source of graphite and multi-layer graphene: Preparation of nanocomposites exhibiting strongly anisotropic electrical conductivity

•Calcination of polypyrrole (PPy) at 1300 °C leads to a formation of graphite.•Montmorillonite (Mt) and ghassoul (Gha) reduce disorder of the graphite.•Multi-layer graphene was formed in calcined PPy/Gha nanocomposite.•Electrical conductivity (EC) of calcined nanocomposites exceeds EC of calcined PPy.•Anisotropy in EC of the nanocomposites reached three orders of magnitude. Nanocomposite tablets containing graphite and multi-layer graphene formed from polypyrrole (PPy) in the presence of Na-montmorillonite (Mt) and Moroccan clay ghassoul (Gha) were prepared by the calcination of PPy/Mt and PPy/Gha intercalates in argon at 1300 °C. XPS, XRD, Raman, and TEM analyses confirmed that PPy can serve as a precursor of graphite and multi-layer graphene. Although the calcined tablets PPy/Mt(c) and PPy/Gha(c) contain ~ 1/3 of the carbon content compared to a calcined PPy tablet (PPy(c)), the mean values of in-plane electrical conductivity (2476 S/m for PPy/Mt(c) and 2289 S/m for PPy/Gha(c)) are higher than 1837 S/m obtained for PPy(c). Strong anisotropy in electrical conductivity (three orders of magnitude) was achieved for PPy/Mt(c) and PPy/Gha(c) tablets. The similar conductivity, as well as density, porosity, and hardness of PPy/Mt(c) and PPy/Gha(c), demonstrate that Mt and Gha in conjunction with PPy are suitable for the preparation of nanocomposites with strongly anisotropic electrical conductivity. [Display omitted]