All-electron battery having area-enhanced electrodes
Improved energy storage is provided by exploiting two physical effects in combination. The first effect can be referred to as the All-Electron Battery (AEB) effect, and relates to the use of inclusions embedded in a dielectric structure between two electrodes of a capacitor. Electrons can tunnel through the dielectric between the electrodes and the inclusions, thereby increasing the charge storage density relative to a conventional capacitor. The second effect can be referred to as an area enhancement effect, and relates to the use of micro-structuring or nano-structuring on one or both of the electrodes to provide an enhanced interface area relative to the electrode geometrical area. Area enhancement is advantageous for reducing the self-discharge rate of the device.
1. An electrostatic solid-state energy storage device comprising:
a first electrode;
a second electrode;
a dielectric structure disposed between said first and second electrodes; and
two or more inclusions disposed in said dielectric structure and capable of transferring electrons to or from at least one of said electrodes by tunneling through said dielectric structure;
wherein at least one of said first and second electrodes is vertically micro-structured to provide a greater active area than geometrical area;
wherein said device is capable of storing energy by establishing a charge separation between said inclusions, and wherein said device is capable of providing energy by using said charge separation as an energy source.
2. The device of claim 1 , wherein at least one of said first and second electrodes has an active area to geometrical area ratio of 1.5 or more.
3. The device of claim 1 , wherein said device is a two-terminal device having only said first and second electrodes as external terminals.
4. The device of claim 1 , wherein said first and second electrodes each have a geometrical area of 1 μm 2 or greater.
5. The device of claim 1 , wherein said charge separation between said inclusions is established by application of a voltage of 5V or more between said first and second electrodes.
6. The device of claim 1 , wherein a volume averaged charge separation density of said device when said charge separation is present is 10 −4 e − /nm 3 or greater.
7. The device of claim 1 , wherein said inclusions are selected from the group consisting of: quantum well, quantum wire, quantum dot, and bulk material.
8. The device of claim 1 , wherein said inclusions are arranged according to size to provide a smooth work function gradient of said inclusions.
9. The device of claim 1 , wherein a first of said inclusions is surrounded by several others of said inclusions each having a smaller size than said first inclusion.
10. The device of claim 1 , wherein a first of said inclusions is surrounded by several others of said inclusions each having a larger size than said first inclusion.
11. The device of claim 1 , wherein some or all of said inclusions are organized as functional layers disposed in or on said dielectric structure.
12. The device of claim 11 , wherein said functional layers comprise different materials having different work functions, and wherein said functional layers are disposed to form a Fermi level gradient.
13. The device of claim 11 , wherein said functional layers comprise a material having an electron affinity that is lower than an electron affinity of part or all of said dielectric structure.
14. The device of claim 11 , wherein two or more of said functional layers are arranged in a multi-layer stack and separated from each other by one or more barrier layers.
15. The device of claim 1 , wherein said dielectric structure comprises two or more dielectric layers.