Empowering Ultracapacitors with Chemically Modified Graphene Materials
Background There are two types of electrical energy storage devices: chemical energy storage (batteries) and electrochemical dual-layer capacitors (ultracapacitors). Ultracapacitors are widely used for energy recapture, energy storage, backup power supplies, and power conditioning applications. They are known for their excellent cycle lifetimes, high power densities, high efficiencies, tolerance to deep discharge and overcharging, broad temperature tolerance, and low energy densities
Ultracapacitors can be used by themselves or in combination with batteries or fuel cells as a secondary power source. They are especially suited for applications requiring short time durations for energy capture and/or delivery. It is anticipated that ultracapacitors will become an increasingly important energy storage component for power sources. Battery efficiencies can be as low as 50% when subjected to short charge/discharge cycles, whereas ultracapacitors are on the order of 90%. An ultracapacitor can be used in a wide range of energy storage applications.
Ultracapacitors can be ideal for any application having a short load cycle, high reliability requirement, such as energy recapture sources including load cranes, forklifts, and electric vehicles. Other applications that can utilize the nearly instantaneous ability to absorb and release power include power leveling for electric utilities and factory power backup. A bank of ultracapacitors, for example, can bridge a short gap between a power failure and the startup of backup power generators.
Invention Description This technology proposes the use of a Chemically Modified Graphene (CMG) sheet material in ultracapacitors, in order to leverage their very high surface areas for increased gains in energy density, ability to assemble a range of morphologies that enable compatibility with high voltage electrolytes, and high conductivity for high power densities.
High power capability Long life Wide temperature operating ranges Low weight Flexible packaging Low maintenance
Source of high energy density
Market Potential/Applications The use of CMGs in ultracapacitors address several of the limitations currently facing commercialization of ultracapacitors, such as the limited volumetric energy storage, limited power density, and the limited ability to operate in extreme temperatures.
Development Stage Proof of concept
IP Status One U.S. patent application filed
UT Researcher Rodney Ruoff, Mechanical Engineering, The University of Texas at Austin Meryl Stoller, Mechanical Engineering, The University of Texas at Austin
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