Supercapacitor

Supercapacitors store charge at the electrode-electrolyte interface rather than through bulk redox, trading energy density for power density, cycle life, and millisecond-scale response. This discipline node groups the experimental work that sits between batteries and dielectric capacitors: electric double-layer capacitors (EDLCs), pseudocapacitors, and hybrid (battery-type plus capacitor-type) cells.

Researchers in this area span three overlapping families of devices:

• EDLCs — non-faradaic charge storage on high-surface-area carbons (activated carbon, carbide-derived carbon, templated carbons, graphene, CNTs) in organic, aqueous, or ionic-liquid electrolytes.
• Pseudocapacitors — fast surface or near-surface faradaic processes on transition-metal oxides (RuO2, MnO2, Nb2O5), nitrides, and conducting polymers (PEDOT, PANI, PPy).
• Hybrid devices — one battery-type electrode paired with one capacitor-type electrode, including lithium-ion capacitors (LICs), sodium-ion capacitors, and aqueous zinc- or nickel-based hybrids.

Standard characterization is electrochemical: cyclic voltammetry to separate capacitive from diffusion-controlled current, galvanostatic charge-discharge for capacitance and energy/power, and electrochemical impedance spectroscopy for ESR and time-constant analysis. Long-cycle and float-voltage testing matter more here than in most battery work because the value proposition of the device is lifetime and rate.

Material selection is driven by accessible surface area, pore-size matching to electrolyte ion size, and stability window — wider potential windows in acetonitrile- or ionic-liquid-based electrolytes raise energy density at the cost of conductivity and cost.

Supporting materials and equipment for this discipline — carbon powders, current collectors, separators, binders, organic and ionic-liquid electrolytes, coin and pouch cell hardware, and potentiostats — are distributed across the rest of the catalog under their respective material and equipment collections.