All three nanostructured electrodes see the same applied current. The porous-carbon EDLC stores charge purely electrostatically: ions physically adsorb onto its surface into a rigid double layer — fast, but capacity is capped by surface site count. The metal-oxide pseudocapacitor adds a fast, reversible surface redox step: each docked ion briefly exchanges an electron with the oxide (the flash) before settling, so it stores more charge per site at nearly EDLC speed — no slow solid-state diffusion required. The battery electrode instead relies on bulk intercalation: ions must random-walk deep into the material's interior, layer by layer, which is far slower but unlocks vastly more total storage sites in the bulk, not just the surface.
EDLC: Q = C_dl · V (surface adsorption only)
Pseudocap: Q = C_dl·V + n·F·Γ(V) (+ fast surface redox)
Battery: Q ∝ ∫ D·∇c dt (slow bulk diffusion)
- Applied current — scales how many ions arrive per second at all three electrodes simultaneously, i.e. the shared C-rate.
- EDLC — ions settle the instant they touch a free surface site; no chemistry, no delay, but the site count is fixed by exposed surface area.
- Pseudocapacitor — same fast docking, plus a brief colour flash marking the faradaic electron transfer; each site then holds more charge than a purely electrostatic one.
- Battery — ions keep drifting downward through the lattice after arriving; charge only counts once an ion settles into a layer, so the curve lags — but the bulk has far more sites than either surface electrode.
Real-world relevance: this three-way contrast is exactly why supercapacitor researchers chase pseudocapacitive nanomaterials (RuO₂, MnO₂, MXenes) — they promise battery-like energy density from the fast, power-dense kinetics of a capacitor, sitting in the gap between EDLC supercapacitors and diffusion-limited batteries.