Table 2.

Inter-graphene sheets distance—d—determined from XRD, C/O ratios calculated from XPS atomic concentration data, and electrical conductivities recorded for Si-GHG 1 h and 18 h compared to that of Si@C-GHG 1 h and 18 h. Densities of Si-GHG-18h and Si@C-GHG-18h are reminded.

Samples	d (nm)	C/O	σ (S/m)	ρ (g/L)
Si-GHG-1h	0.37	1.7	232	-
Si-GHG-18h	0.37	1.8	308	0.04
Si@C-GHG-1h	0.35	3.1	388	-
Si@C-GHG-18h	0.35	3.0	696	0.11