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Posted: Dec 23, 2010
Angstron Materials Invents Graphene-based Supercapacitor With Ultra-high Energy Density
(Nanowerk News) Angstron Materials Inc., has invented a graphene-based supercapacitor with ultra high energy density, a feature that permits storage of a significant amount of energy. As a rechargeable energy storage device, supercapacitors can be charged and discharged more quickly than batteries but have been challenged by their inability to store energy in the amounts required by automotive and electronic applications. Angstron's graphene-based supercapacitor has demonstrated an energy density that exceeds that of commercially available supercapacitors and is comparable with nickel metal hydride batteries.
"A supercapacitor that can store this much energy yet be completely charged or discharged in seconds or minutes offers a number of promising applications for the automotive and electronics industries," said Dr. Bor Jang, co-founder of Angstron. "This type of supercapacitor is especially attractive for electric vehicle applications where the pairing of supercapacitors with fuel cells or batteries could provide a hybrid system capable of delivering high power acceleration and energy recovery during braking."
The world's largest producer of nano graphene platelets (NGPs), Angstron's single layer graphene has exhibited the highest electrical properties including exceptional in-plane electrical conductivity (up to ~ 20,000 S/cm) when compared to other nanomaterials including carbon nano-tubes (CNTs) and carbon nano-fibers (CNFs). Graphene also offers a very high specific surface area - up to 2675 square meters per gram. By creating curved graphene sheets that resist restacking, Angstron was able to dramatically improve specific surface area and energy density for greater energy storage.
"The risk during the manufacture of the electrode is that the graphene layers could be pushed back together," Dr. Jang explained. "We eliminated the problem of potential restacking by creating curved graphene sheets. This allows us to maintain an optimal surface area for more energy storage. The graphene electrode also enables fast charging and discharging of the supercapacitor. This development has pushed the specific energy density of an electrical double-layer (EDL) graphene-enabled supercapacitor to an unprecedented level of nearly 90 watt hours per kilogram at room temperature and a level of 136 watt hours per kilogram at 80° Celsius."
Angstron Materials offers a variety of graphene materials in sizes ranging from nano to micron in the x, y and z axis. These advanced materials are collectively referred to as nano graphene platelets (NGPs). NGPs offer improved material performance and superior mechanical, thermal, barrier and electrical conductivity properties. As a result, Angstron is able to work with companies to functionalize graphene for specific applications that include batteries, fuel cells, supercapacitors, light weight structural components as well as electromagnetic interference (EMI), radio frequency interference (RFI), electrostatic discharge (ESD), lightning strike and other functional and structural composite applications. Angstron uses its research and development expertise to partner with customers throughout the commercialization process, reducing time and costs while improving performance. NGPs are surface functionalizable for polymer and common solvent applications and can offer loadings of up to 40 percent weight for a variety of applications. Angstron combines real world technology to create next generation products in the aerospace, automotive, energy, marine, construction, electronics, medical, military and telecommunications markets.