Electronic devices supercapacitors

Flexible electrochromic devices (ECDs) are becoming increasing important for their promising applications in many areas, such as the portable and wearable electronic devices, including smart windows, functional supercapacitors, and flexible displays. Typically, an ECD consists of four parts of substrate, conductive electrode, electrochromic material, and electrolyte. Enormous efforts have been made to improve the flexibility of ECDs including utilizing flexible polymer substrates and conductive materials. 

These remarkable electrochemical properties have many potential applications, in batteries, electrochromic display devices, supercapacitors and, more recently, for the conception and production of various sensors for molecular electronics. The main problem, however, is cycling reversibility, which will determine the suitability of PPP for these applications. The electroactivity of a given PPP depends on several factors, particularly on the nature of solvent and electrolyte, and on the potential range at which it is cycled. 

Electrochemical double-layer capacitors, often called supercapacitors, can store energy via reversible interfacial electrosorption of ions, and are used to power portable electronic equipment, hybrid electronic vehicle, and other devices. Supercapacitors have fast-charging and discharging rates and the ability to sustain millions of cycles. They bridge the gap between the batteries that offer high energy densities but are slow and between conventional electrolytic capacitors that are fast but have low energy densities. 

An electrochemical capacitor is a device that stores electrical energy in the electrical double layer that forms at the interface between an electrolytic solution and an electronic conductor. The term applies to charged carbon—carbon systems as well as carbon-battery electrode and conducting polymer electrode combinations sometimes called ultracapacitors, supercapacitors, or hybrid capacitors. 

In the late 1980s, the system was reconsidered by Quadri Electronics who produced an improved supercapacitor under the trade name HYPERCAP . Very high rate and peak power capabilities - current pulses in excess of 10 A with rise times of the order of milliseconds, and 3 kW/kg, respectively - have been reported for these solid state devices. 

Debra R. Rolison is head of Advanced Electrochemical Materials at the Naval Research Laboratory (NRL). She received a B.S. in chemistry from Florida Atlantic University in 1975 and a Ph.D. in chemistry from the University of North Carolina at Chapel Hill in 1980 under the direction of Royce W. Murray. Dr. Rolison joined the Naval Research Laboratory as a research chemist in 1980. Her research at NRL focuses on the influence of nanoscale domains on electron- and charge-transfer reactions, with special emphasis on the surface and materials science of aerogels, electrocatalysts, and zeolites. Her program creates new nano structured materials and composites for catalytic chemistries, energy storage and conversion (fuel cells, supercapacitors, batteries, thermoelectric devices), and sensors. 

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