Elektrodlängd

Elektrodlängd is a geometric parameter describing the linear extent of the active part of an electrode that is in contact with an electrolyte. It represents the length along the electrode’s surface that participates in electrochemical reactions and is exposed to the solution. In practice, elektrodlängd is defined as the portion of the electrode surface that contributes to faradaic processes, while insulated or unsupported sections are not counted.

Electrode length is usually considered together with other dimensions, such as width or radius, to determine the active surface area. For a planar rectangular electrode, the area scales with length, while for cylindrical or wire-like electrodes the area depends on both length and circumference, with end effects potentially adding or reducing the effective area depending on whether the ends are exposed to the electrolyte.

The length influences the electrochemical response mainly through the active surface area and the resulting current for a given concentration and potential. Longer electrodes typically offer more surface area, which can increase mass-transport-limited current under the same conditions, although the precise relationship depends on geometry and the diffusion regime. In diffusion-controlled systems, current is related to area and diffusion coefficients, while in microelectrode configurations, diffusion can approach hemispherical behavior, altering the dependence on length. Electrical resistance along the electrode and nonuniform current distribution can also be affected by length, with implications for impedance and noise.

In practical terms, elektrodlängd is controlled during fabrication by methods such as machining, deposition, or lithography, and is reported together with other dimensions to characterize the electrode in experiments and devices.