Graphene is sheets of carbon atoms one atom thick, arranged in a hexagonal (honeycomb-like) lattice. Graphene has the highest known current density at room temperature (a million times that of copper) and the highest intrinsic mobility of any known material (100 times higher than silicon). This means that it can carry more electricity, faster, and with more precision than any other material. Graphene is also mechanically 100 times stronger than steel, transparent, and retains its conducting properties even when bent or stretched. It also has no band gap (the gap between the energy of an electron when it is bound to an atom and the so-called conduction band, where it is free to move around), making it an excellent candidate for use in highly efficient photovoltaic (PV) cells.
• Graphene can be used as a performance-enhancing material in composites to add strength, stability, electrical and thermal conductivity, and other attributes at lower loading levels than traditional materials. Its unique structure and properties provide different application opportunities from standard carbon additives.
• Graphene can be utilised effectively in the form of graphene nanoplatelets: these are as stiff and strong as carbon nanotubes, but shaped like flat plates of graphene several layers thick. These nanoplatelets can be between 5 - 15 microns in diameter and 0.7 - 10 nanometers in thickness. They can be readily surface-functionalised and easily dispersed in a variety of common solvents and monomers, facilitating their incorporation into composite materials.
• Graphene-containing formulations offer the ability to break traditional design trade-offs in composite materials. Its tensile strength and excellent thermal and electrical conduction properties make graphene a truly multi-functional filler. The result is improved performance and enhanced cost-effectiveness for polymeric materials, including thermoplastic and thermoset composites, natural or synthetic rubber, thermoplastic elastomers, adhesives, paints and coatings.
• Graphene is widely used as a basic component of supercapacitors, devices which store as much power as batteries, but can be charged and discharged in seconds. They deliver quick bursts of energy during peak load, then capture and store excess energy which would otherwise be lost.
The chemical structure of graphene ensures complete flexibility of the supercapacitors, which translates into their superior performance under high mechanical stress, guaranteeing a long operating lifetime. Graphene-based supercapacitors could also be used at extreme temperatures.
Where supercapacitors make a real difference
Supercapacitors are invaluable for use in transport. They can harvest and store energy from regenerative braking systems, releasing it in short bursts of power during acceleration. That drastically reduces the fuel consumption in an internal combustion engine, and battery drain in electric/hybrid systems.
Due to their robust nature, low maintenance requirements and long operating life, they can withstand harsh operating conditions, such as high duty cycles, peak currents and frequent deep discharging, and are reliable even in extreme weather.
Our everyday life depends on uninterruptible power suppy energy: think of hospitals, computing, banking, telecommunications and broadcasting as well as complex industrial processes and security. Even a short-term interruption can be crippling, resulting in a loss of data, business and potentially life. Supercapacitors ensure reliable short-term bridge power to allow a network to be switched to another power source or gracefully shut down.
Supercapacitors are widely used in wind turbines as a backup power source to the pitch control system, to ensure system safety and stability.
High reliability, efficiency, near-zero maintenance and long operating lifetime makes supercapacitors ideal for remote and offshore wind power applications.
Due to their ability to charge and discharge in seconds, the reliability and long operating life of supercapacitors can transform any consumer electronics, e.g. cameras, kitchen appliances, toys, etc. The use of supercapacitors results in lighter and smaller devices without affecting performance.
As renewables account for an ever-increasing percentage of total grid power, grid stability becomes a vitally important issue. However, wind power and solar energy are subject to inevitable fluctuations due to weather conditions, destabilising grid. Supercapacitors provide power buffering between the wind turbines and solar panels and the electrical grid, to ensure efficient long-term operation in all weather conditions, with minimal maintenance.
Graphene is the strongest material ever tested by man. Adding graphene to materials such as plastic and rubber to create composites can generate materials with vastly improved stiffness, thermal stability and chemical and environmental resistance. Graphene is also extremely conductive, both electrically and thermally, providing anti-static properties to composites and reducing heat buildup. Improved properties of graphene composites were obtained at very low graphene contents, and graphene-reinforced composites are simultaneously tougher and lighter than generic composite materials.
The unique qualities of graphene offer much potential for developing lightweight, high-performance composite materials for a wide range of applications.