Energy storage system using rare earth and hydroxyl co-doped ceramic in humid-environment

• US 10,325,724 B2
• Filed: 03/29/2017
• Issued: 06/18/2019
• Est. Priority Date: 03/29/2017
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States of America as represented by the Administrator of NASA
• Inventors: Rolin, Terry D., Small, Ian K., Hill, Curtis W.
• Primary Examiner(s): Thomas, Eric W
• Assistant Examiner(s): Ramaswamy, Arun
• Application Number:
  US15/473,364
• Publication Number:
  US 20180286590A1
• Time in Patent Office: 811 Days
• Field of Search: 3613211, 361523, 3613212, 361311, 3613014
• CPC Class Codes: C04B 2235/3201 Alkali metal oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3203 Lithium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3215 Barium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3227 Lanthanum oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3236 Alkaline earth titanates
• CPC Class Codes: C04B 2235/36 Glass starting materials for making ceramics, e.g. silica glass
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/5445 submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/5454 nanometer sized, i.e. below 100 nm
• CPC Class Codes: C04B 2235/656 characterised by specific heating conditions during heat treatment
• CPC Class Codes: C04B 2235/96 Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
• CPC Class Codes: C04B 35/4682 based on BaTiO3 perovskite phase
• CPC Class Codes: C04B 35/6262 of calcined, sintered clinker or ceramics
• CPC Class Codes: H01G 4/005 Electrodes
• CPC Class Codes: H01G 4/1227 based on alkaline earth titanates
• CPC Class Codes: H01G 4/224 Housing; Encapsulation
• CPC Class Codes: H01G 4/30 Stacked capacitors H01G4/33 takes precedence
• CPC Class Codes: H01G 4/38 Multiple capacitors, i.e. structural combinations of fixed capacitors
• CPC Class Codes: H01M 6/185 with oxides, hydroxides or oxysalts as solid electrolytes
• CPC Class Codes: H01M 8/0217 Complex oxides, optionally doped, of the type AMO3, A being an alkaline earth metal or rare earth metal and M being a metal, e.g. perovskites
• CPC Class Codes: Y02E 60/50 : Fuel cells

Abstract

An energy storage system includes a hermetically-sealed casing defining a volume whose relative humidity is a range of 30-90%. At least one energy storage capacitor disposed in the volume has a solid dielectric sandwiched between two electrodes with the solid dielectric being a lanthanum-doped barium titanate-based ceramic material.

Claims

1. An energy storage system, comprising:

a hermetically-sealed casing having a volume defined within the casing wherein a relative humidity in said volume is a range of 30-90%; and

at least one energy storage capacitor disposed in said volume, each said energy storage capacitor having a solid dielectric sandwiched between two electrodes, wherein said solid dielectric is a lanthanum-doped barium titanate-based ceramic material, wherein a dopant of said lanthanum-doped barium titanate-based ceramic material is selected from the group consisting of lanthanum hydroxide and lanthanum oxide, and wherein said lanthanum-doped barium titanate-based ceramic material includes an alkali hydroxide co-dopant selected from the group consisting of potassium hydroxide, sodium hydroxide, rubidium hydroxide, and lithium hydroxide.

2. An energy storage system as in claim 1, wherein said casing is made from a material selected from the group consisting of plastics, ceramics, and metals.

3. An energy storage system as in claim 1, wherein said at least one energy storage capacitor comprises a plurality of energy storage capacitors in a stacked arrangement.

4. An energy storage system as in claim 1, wherein each said solid dielectric has a thickness in a range of 1-50 micrometers.

5. An energy storage system as in claim 1, wherein said relative humidity in said volume is a range of 50-90%.

6. An energy storage system, comprising:

a hermetically-sealed casing having a volume defined within the casing wherein a relative humidity in said volume is a range of 30-90%; and

a stacked arrangement of a plurality energy storage capacitors disposed in said volume, each of said energy storage capacitors having a solid dielectric sandwiched between two electrodes, wherein said solid dielectric is a lanthanum-doped barium titanate-based ceramic material having a thickness in a range of 1-50 micrometers, wherein a dopant of said lanthanum-doped barium titanate-based ceramic material is selected from the group consisting of lanthanum hydroxide and lanthanum oxide, and wherein said lanthanum-doped barium titanate-based ceramic material includes an alkali hydroxide co-dopant selected from the group consisting of potassium hydroxide, sodium hydroxide, rubidium hydroxide, and lithium hydroxide.

7. An energy storage system as in claim 6, wherein said casing is made from a material selected from the group consisting of plastics, ceramics, and metals.

8. An energy storage system as in claim 6, wherein said relative humidity in said volume is a range of 50-90%.

9. An energy storage system, comprising:

a hermetically-sealed casing having a volume defined within the casing wherein a relative humidity in said volume is a range of 30-90%; and

at least one energy storage capacitor disposed in said volume, each said energy storage capacitor having a solid dielectric sandwiched between two electrodes, wherein said solid dielectric is a lanthanum-doped barium titanate-based ceramic material, wherein a dopant of said lanthanum-doped barium titanate-based ceramic material comprises lanthanum hydroxide, and wherein said lanthanum-doped barium titanate-based ceramic material includes an alkali hydroxide co-dopant selected from the group consisting of potassium hydroxide, sodium hydroxide, rubidium hydroxide, and lithium hydroxide, each said energy storage capacitor prepared by a process comprising the steps of

providing particles of lanthanum hydroxide having an average grain diameter of 50-700 nanometers, particles of barium oxide having an average grain diameter of 50-700 nanometers, and particles of titanium dioxide having an average grain diameter of 50-700 nanometers,

mixing 0.7-5.0 weight percent of said particles of lanthanum hydroxide, 60-65 weight percent of said particles of barium oxide, and a remaining weight percent of said particles of titanium dioxide, wherein a mixture of particles is generated,

heating said mixture of particles to a temperature in a range of 1000−

1300°

C. wherein a sintered mixture is generated,

milling said sintered mixture to generate milled particles having diameters of 50-700 nanometers,

mixing 50-70 weight percent of said milled particles with

5-15 weight percent of glass particles having a particle size of 0.5-10 micrometers,

0.1-5.0 weight percent of an organic surfactant,

5-25 weight percent of a solvent,

5-25 weight percent of an organic vehicle, and

1-5 weight percent of said alkali hydroxide, wherein a liquid mixture is generated,

providing a first electrode of said two electrodes,

depositing a layer of said liquid mixture onto said first electrode,

processing said first electrode with said layer thereon to remove liquid portions of said liquid mixture, wherein said step of processing includes a cycle of heating said layer to a temperature in a range of 850-900°

C. followed by a cycle of cooling said layer in a nitrogen atmosphere containing less than 25 parts per million of oxygen, and

affixing a second electrode of said two electrodes onto said layer after said liquid portions of said liquid mixture have been removed.

10. An energy storage system as in claim 9, wherein said step of heating said mixture of particles occurs in air.

11. An energy storage system as in claim 9, wherein said step of heating said mixture of particles occurs in a vacuum.

12. An energy storage system as in claim 9, wherein said layer is 1-50 micrometers in thickness.

13. An energy storage system as in claim 9, wherein said organic surfactant is selected from the group consisting of phosphate esters.

14. An energy storage system as in claim 9, wherein said solvent is selected from the group consisting of ester alcohol, terpineol, and butyl carbitol.

15. An energy storage system as in claim 9, wherein said organic vehicle comprises ethyl cellulose.

16. An energy storage system as in claim 9, wherein said glass particles are selected from the group consisting of lead germinate glass particles and zinc borate glass particles.

17. An energy storage system as in claim 9, wherein said relative humidity in said volume is a range of 50-90%.