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 SiO 2 or SiO x N y dielectric layer 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, and wherein the first blocking layer comprises a cation conducting material and the second blocking layer comprises an anion conducting material.
2. The device of claim 1 , wherein the first and second blocking layers independently comprises a material having a breakdown field strength of between 1 mV/nm and 200 mV/nm.
3. The device of claim 1 , wherein the cation conducting material is selected from Mg 2+ , Li + , H + , and Na + conductors, and wherein the anion conducting material is selected from O − and F − conductors.
4. The device of claim 3 , wherein the cation conducting material is a Li + conductor selected from Li 3 PO 4 and Li 3 PO 4-x N x .
5. The device of claim 1 , wherein the first and second blocking layers independently comprises a material having a dielectric constant between 10 and 10000 times the dielectric constant of the material comprising the dielectric layer.
6. The device of claim 1 , wherein the first and second blocking layers independently have a thickness of between 4 nm and 100 nm.
7. The device of claim 1 , wherein the dielectric layer has a thickness of between 10 nm and 10 um.
8. The device of claim 1 , wherein the first and second blocking layers independently have a thickness of between 10 and 1000 times the thickness of the dielectric layer.
9. The device of claim 1 , wherein the first blocking layer further comprises an anion conducting material.
10. The device of claim 9 , wherein the second blocking layer further comprises a cation conducting material.
11. The device of claim 1 , wherein the device has an energy density of between 50 and 500 Whr/kg.
12. The device of claim 1 , wherein the device has an energy density of greater than 50 Whr/kg.
13. The device of claim 12 , wherein the device has an energy density of greater than 100 Whr/kg.
14. The device of claim 1 , wherein the first electrode has a work function greater than the work function of the second electrode.
15. The device of claim 14 , 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.