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Institute Reference: INV-1266
Background
It is understood well that supercapacitors improve storage density through the use of a porous material that increases the specific area of the electrodes. There has been interest in using carbon-based nanomaterials as supercapacitor electrodes due to several advantages of carbon, such as light weight, high electrical conductivity, and electrochemical surface area. Activated carbon (AC) has received a lot of attention and has been used in supercapacitor designs as a good electrode material due its high surface area. It is currently the material of choice for both low and high voltage applications.
However, with AC, the use of binders and conducting agents hinders the capacitance and results in a long-term degradation due to the particulate nature of AC in the presence of uncontrolled functional groups. Recently, other types of carbon materials such as carbon aerogel, carbon black, carbon nanotubes (CNTs) and graphene have been used for developing improved supercapacitors. High surface area in these carbon materials is generally characteristic of a highly developed nanostructure. Nanomaterials can also have controlled chemical composition and tailored physical architectures down to nanoscale dimensions. They are randomly oriented with respect to the current collectors in a stacked geometry in supercapacitors. There would be a large number of interesting new designs for energy storage devices if carbon electrodes could be tailored and engineered in forms that would avoid the problems outlined above.
Technology Overview
This Northeastern University invention provides flexible and transparent supercapacitors using thin carbon films fabricated inside porous templates by chemical vapor deposition. These carbon films contain arrays of periodic and interconnected “carbon nanocup” (CNC) structures composed of few layers of carbon material having a graphitic structure. The CNC-containing carbon films are used as thin-film electrodes for supercapacitor devices of the invention. CNCs have an architecture that is precisely engineered from graphitic carbon deposited within porous templates. The CNCs have much smaller (up to 10.sup.5 times smaller) length/diameter (L/D) ratios compared to conventional carbon nanotubes, and have a unique nanoscale cup morphology.
Composites made of these CNC films with polymer electrolyte have three remarkable features that render them highly useful in a solid state, thin-film supercapacitor device. First, the CNC film has a high surface area afforded by an array of controlled nanoscale cup structures and highly disordered graphitic layers; this feature is key for the effective permeation of the polymer electrolyte required in supercapacitors. Second, the unique nanoscale structural and morphological features of CNC films enable easy access and fast transport of ions at the electrode/electrolyte interface, resulting in high power capability. Finally, the high current carrying capability, substantial mechanical strength, and small effective electrode thickness (e.g., about 10 nm) allow the supercapacitor material of the invention to be used for building multifunctional, optically transparent, mechanically flexible, and reliable thin-film energy storage devices.
Benefits
The carbon nano-material:
• Comprises a unique nano-scale cup morphology
• Is light weight with high electrical conductivity as compared to conventional materials
• Has a higher electrochemical surface area with a porous template
• Has a higher mechanical strength and current carrying capacity as compared to conventional materials
•Has 105 times smaller length/diameter ratio as compared to conventional nanotubes
• Enables a faster transport of ions, allowing for a higher power capability as compared to conventional approaches
• Allows for the development of high capacity (3-5 times higher) energy storage devices
• Is commercially useful for various applications such as in organic solar cell platforms
Applications
- Consumer Electronics (smartphones, displays)
- Healthcare (sensors)
- Automotive/Architectural (smart/switchable glass)
- Other applications where power sources need to be flexible and transparent
Opportunity
- Development partner
- Commercial partner
- Licensing
Patents
IP Status
