Dielectric Particle Processing for Ultracapacitance

• US 20180102224A1
• Filed: 12/12/2017
• Published: 04/12/2018
• Est. Priority Date: 01/29/2016
• Status: Active Grant

• Current Assignee: United States of America as represented by the Administrator of NASA
• Original Assignee: United States of America as represented by the Administrator of NASA
• Inventors: Rolin, Terry D., Hill, Curtis W.
• Granted Patent: US 10,453,621 B2
• Time in Patent Office: Days
• CPC Class Codes: C03C 8/20 containing titanium compounds; containing zirconium compounds
• CPC Class Codes: C04B 2235/3215 Barium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3236 Alkaline earth titanates
• CPC Class Codes: C04B 2235/3418 Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
• CPC Class Codes: C04B 2235/36 Glass starting materials for making ceramics, e.g. silica glass
• CPC Class Codes: C04B 2235/365 Borosilicate glass
• CPC Class Codes: C04B 2235/5445 submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/6026 Computer aided shaping, e.g. rapid prototyping
• CPC Class Codes: C04B 2235/6562 Heating rate
• CPC Class Codes: C04B 2235/6567 Treatment time
• CPC Class Codes: C04B 2235/6584 at an oxygen percentage below that of air
• CPC Class Codes: C04B 2235/6586 Processes characterised by the flow of gas
• CPC Class Codes: C04B 2235/768 Perovskite structure ABO3
• 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 35/62222 obtaining ceramic coatings coating of mortars, concrete, artificial or natural stone or ceramics C04B41/45; laminated ceramic products B32B18/00; coating metallic materials C23; coating of glass C03C17/00, applying ceramic coatings on silicon for semi-conductor purposes H01L
• CPC Class Codes: C04B 35/6262 of calcined, sintered clinker or ceramics
• CPC Class Codes: C04B 35/6264 Mixing media, e.g. organic solvents
• CPC Class Codes: C04B 35/6265 involving reduction or oxidation
• CPC Class Codes: C04B 35/6268 : characterised by the applied pressure or type of atmosphere, e.g. in vacuum, hydrogen or a specific oxygen pressure
• CPC Class Codes: C04B 35/62807 : Silica or silicates
• CPC Class Codes: C04B 35/62813 : Alumina or aluminates
• CPC Class Codes: C04B 35/62884 : by gas phase techniques
• CPC Class Codes: C04B 35/62897 : Coatings characterised by their thickness
• CPC Class Codes: C04B 35/6303 : Inorganic additives
• CPC Class Codes: C04B 35/6316 : Binders based on silicon compounds
• CPC Class Codes: C04B 35/632 : Organic additives
• CPC Class Codes: C04B 35/638 : Removal thereof
• CPC Class Codes: C04B 35/64 : Burning or sintering processes C04B33/32 takes precedence ; powder metallurgy B22F
• CPC Class Codes: H01G 11/46 : Metal oxides
• CPC Class Codes: H01G 11/56 : Solid electrolytes, e.g. gels; Additives therein
• CPC Class Codes: H01G 11/84 : Processes for the manufacture of hybrid or EDL capacitors, or components thereof
• CPC Class Codes: H01G 4/1227 : based on alkaline earth titanates
• CPC Class Codes: H01G 4/30 : Stacked capacitors H01G4/33 takes precedence
• CPC Class Codes: H01G 4/33 : Thin- or thick-film capacitors thin- or thick-film circuits H01L27/00; capacitors without a potential-jump or surface barrier specially adapted for integrated circuits, details thereof, multistep manufacturing processes therefor H01L28/40
• CPC Class Codes: H01G 7/06 : having a dielectric selected for the variation of its permittivity with applied voltage, i.e. ferroelectric capacitors electrets H01G7/02
• CPC Class Codes: Y02E 60/13 : Energy storage using capacitors

Abstract

An ink of the formula: 60-80% by weight BaTiO₃ particles coated with SiO₂; 5-50% by weight high dielectric constant glass; 0.1-5% by weight surfactant; 5-25% by weight solvent; and 5-25% weight organic vehicle. Also a dielectric made by: heating particles of BaTiO₃ for a special heating cycle, under a mixture of 70-96% by volume N₂ and 4-30% by volume H₂ gas; depositing a film of SiO₂ over the particles; mechanically separating the particles; forming them into a layer; and heating at 850-900° C. for less than 5 minutes and allowing the layer to cool to ambient temperature in N₂ atmosphere.

Claims

1. A composition of matter comprising:

a) 60-80% by weight BaTiO₃ particles coated with a 3-20 nm film of SiO₂ or a 3-10 nm thick film of Al₂O₃;

said BaTiO₃ particles having an average grain diameter of 100-700 nm;

said BaTiO₃ having doubly ionized oxygen anion vacancies;

b) 5-50% by weight high dielectric constant glass;

said high dielectric constant glass being 1-10 μ

m in size;

c) 0.1-5% by weight surfactant;

d) 5-25% by weight solvent; and

e) 5-25% by weight organic vehicle.

2. A composition of matter as claimed in claim 1 in which said high dielectric constant glass is lead-germinate glass or zinc borate glass.

3. A composition of matter as claimed in claim 1 in which said surfactant is a phosphate ester.

4. A composition of matter as claimed in claim 1 in which said solvent is ester alcohol, terpineol or butyl carbitol.

5. A composition of matter as claimed in claim 1 in which said organic vehicle is ethyl cellulose.

6. A dielectric made by the process of:

a) obtaining BaTiO₃ particles;

said particles having an average grain diameter of 100-700 nm;

b) treating said particles in a first furnace under a mixture of 70-96% by volume N₂ and 4-30% by volume H₂ gas for 60-90 minutes at 850-900°

C.;

c) coating said treated particles with a 3-20 nm thick film of SiO₂ or a 3-10 nm thick film of Al₂O₃ whereby said coated treated particles become agglomerated;

d) separating said coated, treated particles to break up said agglomeration into individual particles;

e) forming said particles into a layer of sufficient thickness to produce a sintered layer 10-35 μ

m thick; and

f) sintering said layer by heating in a second furnace, at 850-900°

C. for less than 5 minutes and allowing it to cool to ambient temperature under N₂ atmosphere;

said N₂ containing less than 25 ppm O₂.

7. A dielectric as claimed in claim 6 in which said coating process in step c) is atomic layer deposition.

8. A dielectric as claimed in claim 6 in which said separating in step d) is performed by a three roll mill or a high shear mixer.

9. A dielectric as claimed in claim 6 in which said first furnace is a fluidized bed vertical tube furnace.

10. A dielectric as claimed in claim 6 in which said second furnace is a multizone belt furnace.

11. A dielectric as claimed in claim 6 in which during sintering in step f), time under 600°

C. is 30 minutes maximum;

time under 800°

C. is 20 minutes maximum; and

total time is 60-90 minutes.

12. A dielectric as claimed in claim 11 in which, during sintering, the heating rate is 45-55°

C./minute from 300-500°

C.; and

the cooling rate is 45-55°

C./minute from 700-300°

C.