pszeudokapacitás

Pseudokapacitás refers to a phenomenon observed in some electrochemical systems, particularly in certain types of capacitors. It arises when a Faradaic process, which involves a charge transfer reaction, contributes to the overall charge storage mechanism. Unlike ideal electrostatic capacitance where charge storage is purely due to the accumulation of ions at an interface, pseudocapacitance involves redox reactions occurring at the electrode surface or within the bulk of the electrode material.

This charge storage mechanism is characterized by a capacitance that is often significantly higher than what would be expected from purely double-layer capacitance. The redox reactions involved are typically fast and reversible, allowing for rapid charging and discharging, which is a desirable characteristic for energy storage devices. Common materials exhibiting pseudocapacitance include transition metal oxides, conducting polymers, and some carbon-based materials modified with functional groups.

The effective capacitance in a pseudocapacitive system depends on factors such as the applied potential, the concentration of the active redox species, and the kinetics of the electrochemical reaction. While it offers advantages in terms of energy density compared to conventional electrostatic capacitors, it can also lead to a more complex charge-discharge profile and potential degradation issues over time depending on the stability of the Faradaic process. Understanding pseudocapacitance is crucial for the development of advanced electrochemical energy storage devices like supercapacitors with improved performance.