| Amorphous porous carbon |
High surface area, advanced porous system, abundant defective sites, superior chemical inertness |
Relative low conductivity, poor adhesion with FTO |
Consists of an outer spherical shell with porous interior structure, a covalent random network composed of sp3 and sp2 hybridised carbons without grain boundaries, non-crystalline |
High electronic conductivity and high surface area, electronic conductivity and ionic conductivity, with specific capacities of 212 mA h g−1 and 162 mA h g−1 at 0.5C and 1C, respectively |
35
|
| Graphene |
Excellent conductivity, fast charged carrier mobility, good mechanical strength, high optical transparency, good mechanical inertness |
Low surface area arising from the easy aggregation, low quantities of defective sites |
Crystalline carbon materials, monolayers of carbon atoms arranged in a honeycomb network, giant aromatic macromolecule |
Conducts both electricity and heat, thermal conductivity and mechanical stiffness (3000 W m−1 K−1 and 1060 GPa, respectively) |
36
|
| Graphite |
Good conductivity, corrosion resistance, excellent thermal stability |
Poor porous system, low surface area |
Stacks of graphene layers, weak interactions that hold the graphene sheets together |
High electrical and thermal conductivity, thermal conductivity 25 to 470 W m−1 K−1, electrical resistivity 5 × 10−4 to 30 × 10−4 Ω cm |
37 and 38
|
| Carbon black |
Plentiful defective sites, good chemical inertness |
Low surface area, inappropriate pore size, inadequate conductivity |
Typical particle sizes range from around 8 to 100 nm for furnace blacks |
Highly structured carbon blacks provide higher viscosity, greater electrical conductivity and easier dispersion for specialty carbon blacks, electrical volume resistivity between 1 to 106 Ω cm |
39
|
| Carbon nanofibre |
Excellent mechanical strength, high thermal conductivity, good chemical inertness |
Insufficient conductivity, low surface area, inferior porous system |
Cylindrical nanostructures with graphene layers arranged as stacked cones, cups or plates, diameters from 50 to 200 nm |
High electrical conductivity, and high thermal conductivity, intrinsic conductivity, at room temperature to be 5 × 10−5 Ω cm |
40 and 41
|
| Carbon nanotube |
Large surface area, high electrical conductivity, good chemical inertness |
Low quantities of defective sites |
Crystalline carbon materials, most of the physical properties of carbon nanotubes derive from graphene, carbon atoms are densely organised in a regular sp2-bonded atomic-scale honeycomb (hexagonal) pattern, sp2 hybridization of carbon builds a layered construction with weak out-of-plane bonding of the van der Waals form and strong in-plane bounds |
High electrical conductivity, high thermal conductivity, resistivity of the SWCNT is 10−4 Ω cm at 27 °C, the SWCNT ropes able to sustain much higher stable current densities, as high as 1013 A cm−2
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41 and 42
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