Solid state energy storage devices
Described in this patent application are devices for energy storage and methods of making and using such devices. In various embodiments, blocking layers are provided between dielectric material and the electrodes of an energy storage device. The block layers are characterized by higher dielectric constant than the dielectric material. There are other embodiments as well.
1. An energy storage device comprising:
first and second electrodes spaced apart;
a dielectric layer comprising SiO 2 or SiO x N y , and disposed between the first and second electrodes;
a first blocking layer disposed between the first electrode and the dielectric layer; and
a second blocking layer disposed between the second electrode and the dielectric layer,
wherein the dielectric constants of the first and second blocking layers are both independently greater than the dielectric constant of the dielectric layer,
wherein the thicknesses of the first and second blocking layers are both independently less than the thickness of the dielectric layer,
and wherein the first and second blocking layers independently comprise a non-ionically conducting material selected from PZT (Pb(Zr 0.5 Ti 0.5 )O 3 ), SrTiO 3 , PbTiO 3 , BaTiO 3 , (BaSr)TiO 3 , CaCu 3 Ti 4 O 12 , and La 2-x Sr x NiO 4 .
2. The device of claim 1 , wherein the thickness of the dielectric layer is between 1 and 1000 times greater than the thicknesses of the first and second blocking layers independently.
3. The device of claim 1 , wherein the thickness of the dielectric layer is between 1 and 1000 times greater than the thickness of the first blocking layer.
4. The device of claim 1 , wherein the thickness of the dielectric layer is between 1 and 1000 times greater than the thickness of the second blocking layer.
5. The device of claim 1 , wherein the thicknesses of the first and second blocking layers are independently between 4 nm and 100 nm.
6. The device of claim 1 , wherein the thickness of the dielectric layer is between 10 nm and 10 um.
7. The device of claim 1 , wherein the thickness of the dielectric layer is between 20 nm and 10 um.
8. The device of claim 1 , wherein the device has an energy density of between 50 and 500 Whr/kg.
9. The device of claim 1 , wherein the device has an energy density of greater than 50 Whr/kg.
10. The device of claim 1 , wherein the device has an energy density of greater than 100 Whr/kg.
11. The device of claim 1 , wherein the first electrode has a work function greater than the work function of the second electrode.
12. The device of claim 1 , wherein the work function of the first electrode is greater than 4.0 eV and the work function of the second electrode is less than 4.5 eV.