CARBON

The workhorse family

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Carbon-based materials are the most widely used supercapacitor electrodes thanks to high conductivity, large surface area, chemical stability, and long cycling life. They mainly store energy through double-layer capacitance, so they charge fast and barely degrade.

Many different carbon nanostructures exist — each trades something for something else.

CARBON • ACTIVATED CARBON

The commercial standard

Surface area 1,000 – 3,000 m² per gram

Cycle life Frequently over one million cycles

Cost Cheap precursors: coconut shells, wood, coal, polymers

The catch: tiny pores can restrict ion transport, limiting power at fast charging rates and leaving surface area unused.

CARBON • GRAPHENE

One atom thick

Graphene is a single layer of sp²-bonded carbon atoms in a two-dimensional honeycomb lattice. It offers exceptional conductivity, mechanical strength, chemical stability, and a theoretical surface area of about 2,630 m² per gram.

The catch: sheets restack through strong van der Waals forces, shrinking the surface ions can reach. Spacers or 3D architectures are needed to keep them apart.

CARBON • NANOTUBES

Conductive highways

Strengths

Excellent conductivity, mechanical strength, and an interconnected porous network for fast electron and ion transport

Catches

Lower surface area than activated carbon or graphene, high manufacturing cost, and a tendency to bundle

Their 1D shape gives efficient conductive pathways that stay intact through repeated cycling.

CARBON • THE REST

Aerogels, fibers, and cloth

Carbon aerogels, carbon fibers, and carbon cloth combine porous architecture, mechanical flexibility, and excellent conductivity. They're especially attractive for flexible and wearable energy storage.

They often need extra nanostructuring or composite materials to match the capacitance of graphene or activated carbon.

THE GAP

No perfect material

Each carbon offers something, but none delivers everything at once: high conductivity, large accessible surface area, mechanical robustness, chemical stability, biocompatibility, and compatibility with conventional microfabrication.

conductive + stable + biocompatible + patternable = ?

For micro supercapacitors, that last requirement — being patternable with standard lithography — is what points to glassy carbon.

UNIT 11 STUDY COMPLETE

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Ready for the Fab Challenge?

You've covered activated carbon, graphene, nanotubes, and aerogels — strengths and catches of each.