Основные понятия
Graphene's unique property of not fully screening external electric fields can be leveraged to build high-density electrostatic capacitors by stabilizing the electrons on the middle graphene plate using fast AC current-induced Lorentz forces.
Аннотация
The article explores the possibility of using graphene's unique properties to build high-density electrostatic capacitors. Unlike bulk metals, graphene does not completely screen external electric fields, allowing the electric field to penetrate the graphene layer. The author proposes a three-plate capacitor design where the middle plate is made of graphene.
Key insights:
- In a conventional three-plate capacitor with a metallic middle plate, the electric field is screened inside the plate, limiting the maximum electric field and energy density.
- In the graphene-based design, the electric field can penetrate the graphene layer, allowing for higher electric field intensities between the plates.
- However, the negative charges on the graphene middle plate are in an unstable equilibrium, which could lead to electric breakdown.
- To stabilize the electrons, the author proposes using fast AC current oscillations in the graphene layer. The resulting Lorentz forces squeeze the electrons towards the center of the graphene plate, creating an effective trapping potential.
- Numerical modeling shows that the pseudopotential produced by the AC current can exceed 60 eV, much larger than the thermal energy at room temperature, effectively stabilizing the electrons.
- Estimates suggest the electric energy density in such a graphene capacitor could exceed that of gasoline, enabling transformative applications like all-electric aircraft and long-lasting portable electronics.
- The author also describes a potential experiment to validate the electron stabilization concept using a graphene field-effect transistor setup.
Статистика
The maximum current density of 1.18 ×10^8 A/cm^2 was observed for 0.3 μm graphene interconnect on SiO2/Si substrate, leading to a linear current density of 0.35 × 10^5 A/m.
The maximum electron velocity is taken as |vz,max| = 1 × 10^7 m/s.
The maximum magnetic field around the graphene layer is estimated to be 44 mT.
The maximum Lorentz force is estimated to be about 70 fN.
The effective potential produced by the fast oscillations is estimated to be approximately 60 eV, much larger than the thermal energy of 25 meV at room temperature.
The tensile strength of copper side plates is taken as 300 MPa, allowing for a maximum electric energy density of 300 MJ/m^3.
The tensile strength of carbon nanotubes is in the range of 11-63 GPa, potentially enabling electric energy densities exceeding that of gasoline (34.2 GJ/m^3).
Цитаты
"The increase in the maximum electric field intensity leads to an increase of the electric energy density UE= 1/2 ϵ0E^2 stored between the plates of the capacitor."
"Theoretically, the energy density in the triple plate capacitor with side plates made of metallic carbon nanotubes can exceed the one of gasoline. It would correspond to the electric field between the plates exceeding 100 GV/m."