METAL OXIDES

The benchmark: RuO₂

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Ruthenium oxide is considered a benchmark pseudocapacitive material: excellent electrical conductivity, rapid redox kinetics, and exceptionally high specific capacitance. On performance alone, it's hard to beat.

But its high cost, scarcity, and environmental concerns keep it from widespread use.

METAL OXIDES

Cheaper oxides, real limits

Lower-cost alternatives MnO₂, NiO, Co₃O₄, V₂O₅, Fe₂O₃

Conductivity Generally lower than carbon

Durability Repeated redox reactions can degrade the structure

Oxides usually need conductive additives or composite structures to move charge well and stay intact.

CONDUCTING POLYMERS

Charge by doping

Polyaniline (PANI), polypyrrole (PPy), and PEDOT store charge through reversible doping and dedoping during oxidation and reduction. Their relatively high conductivity and large pseudocapacitance let them beat plain double-layer storage.

Low density

Easy to fabricate

Flexible and low-cost

Those traits make polymers attractive for flexible electronics, wearables, and micro supercapacitors.

CONDUCTING POLYMERS

The swelling problem

During charge and discharge, these polymers repeatedly expand and contract. That volume change leads to cracking, mechanical degradation, and lost performance, so conducting polymers generally have shorter cycle lives than carbon-based electrodes.

A common fix: pair the polymer with a carbon material to improve structural stability and conductivity.

UNIT 10 STUDY COMPLETE

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Ready for the Fab Challenge?

You've covered high-capacitance pseudocapacitive materials, and what they cost you in stability.