Superkapazitor

The superkapazitor, often called a supercapacitor in many languages, is a class of energy storage devices that combines attributes of batteries and conventional capacitors. It stores energy primarily through electrostatic charge at the interface between an electrode and an electrolyte (electric double layer) and, in some designs, through fast surface redox reactions (pseudocapacitance). Hybrid configurations also exist that blend capacitor-like and battery-like behavior.

Common constructions use porous carbon materials for the electrodes, with various electrolytes including aqueous, organic, or ionic liquids, separated by a porous separator and connected to current collectors. Two main subclasses are electric double-layer capacitors (EDLCs), which rely on non-faradaic charge storage, and pseudocapacitors, which use rapid surface redox processes. Hybrid supercapacitors combine features of both and may pair different electrode chemistries.

Key performance characteristics include high power density, rapid charge and discharge, and very long cycle life, often exceeding hundreds of thousands to over a million cycles. Energy density is generally lower than that of lithium‑ion batteries, while the device remains effective at high discharge currents and across wide operating temperatures. Typical single-cell voltages are around 2.5–2.7 volts with organic electrolytes, necessitating series configurations for higher voltages in many applications.

Common applications span renewable energy systems, grid stabilization, hybrid and electric vehicles, backup power, and memory preservation in electronics. Limitations include lower energy storage capacity per mass or volume and higher costs per stored energy compared to batteries, though ongoing material advances aim to improve both energy density and cost.