Polymer and molten ion conductive salt and silicon interface for decreased interfacial resistance

Patent metadata

Field	Value
Publication number	US-11205800-B2
Application number	US-201916389012-A
Country	US
Kind code	B2
Filing date	Apr 19, 2019
Priority date	Apr 19, 2019
Publication date	Dec 21, 2021
Grant date	Dec 21, 2021

Abstract

A device such as, for example, an energy storage device or a micro-resistor, is disclosed which includes a silicon based electrode in which decreased interfacial resistance/impedance throughout the charge-mobile region of the device is provided. The decreased interfacial resistance/impedance is provided by forming an interfacial additive composite layer composed of a molten lithium containing salt layer and a layer of a Li-salt containing conductive polymeric adhesive material between the silicon based electrode and a solid polymer electrolyte layer. The presence of such an interfacial additive composite layer increases the ion and electron mobile dependent performances at the silicon based electrode interface due to significant decrease in the resistance/impedance that is observed at the respective interface as well as the impedance observed in the bulk of the device.

First claim

What is claimed is:

1. A device comprising:
a silicon based electrode;
an interfacial additive layer composed of a molten lithium containing salt, wherein the interfacial additive layer has a first surface forming an interface with a surface of the silicon based electrode;
a Li-salt containing conductive polymeric adhesive forming an interface with a second surface of the interfacial additive layer that is opposite the first surface of the interfacial additive layer; and
a solid polymer electrolyte layer forming an interface with the Li-salt containing conductive polymeric adhesive.

2. The device of claim 1 , wherein the silicon based electrode is selected from the group consisting of non-porous silicon, partially porous crystalline silicon, single-crystal non-porous silicon, crystalline silicon, a low resistance doped crystalline silicon, boron doped crystalline silicon and boron doped crystalline porous silicon, wherein the low resistance doped crystalline silicon is of unitary construction and comprises a non-porous region and a porous region, wherein the porous region comprises a top porous layer having a first thickness and a first porosity, and a bottom porous layer having a second porosity that is greater than the first porosity and a second thickness that is greater than the first thickness.

3. The device of claim 1 , wherein the molten lithium containing salt is composed of at least one of lithium hexafluorophosphate, lithium perchlorate, lithium trifluoromethanesulfonate, lithium fluoride, LiBF 4 , lithium chloride, lithium phosphate compounds, lithium bromide compounds, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium difluoro(oxalato)borate (LiDFOB), or lithium bis(oxalato)borate(LiBOB).

4. The device of claim 1 , wherein the solid polymer electrolyte layer is composed of a polymer structure host material, a Li-conductive/plasticizing material and a lithium containing salt.

5. The device of claim 4 , wherein the polymer structure host material is composed of at least one of poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), poly(dimethylsiloxane), poly(vinyl chloride), or polycaprolactone.

6. The device of claim 4 , wherein the Li-conductive/plasticizing material comprises succinonitrile, poly(ethylene glycol) (PEG), an aprotic organic solvent, or any combination thereof.

7. The device of claim 4 , wherein the molten lithium containing salt is composed of at least one of lithium hexafluorophosphate, lithium perchlorate, lithium trifluoromethanesulfonate, lithium fluoride, LiBF 4 , lithium chloride, lithium phosphate compounds, lithium bromide compounds, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium difluoro(oxalato)borate (LiDFOB), or lithium bis(oxalato)borate(LiBOB).

8. The device of claim 1 , wherein the solid polymer electrolyte layer comprises a lower region and an upper region, and wherein a separator is present between the lower region and the upper region.

9. The device of claim 8 , wherein the separator is composed of at least one of polyacrylnitrile (PAN), polyethylene oxide (PEO) based copolymer matrices or structural membranes, a quarternized polysulfone membrane, electrospun polyvinylidene fluoride, or a methylmethacrylate (MMA)/polyethylene (PE) composite.

10. The device of claim 1 , wherein the Li-salt containing conductive polymeric adhesive is composed of a polypyrrol (Ppy), polythiophene, polyaniline (PANI), polyphenylene sulfide, Ppy/carbon nanotube composites, poly(3-(potassium-4-butanoate) thiophene) (PPBT) and poly(ethylene glycol) (PEG) composites, and polystyrene sulfonate and carbon composites.

11. The device of claim 1 , wherein the Li-salt containing conductive polymeric adhesive further comprises a lithium containing salt composed of at least one of lithium hexafluorophosphate, lithium perchlorate, lithium trifluoromethanesulfonate, lithium fluoride, LiBF 4 , lithium chloride, lithium phosphate compounds, lithium bromide compounds, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium difluoro(oxalato)borate (LiDFOB), or lithium bis(oxalato)borate(LiBOB).

12. The device of claim 1 , further comprising a counter electrode located above the solid polymer electrolyte layer.

13. The device of claim 12 , wherein the counter electrode is a second silicon based electrode, and wherein a second Li-salt containing conductive polymeric adhesive and a second interfacial additive layer composed of another molten lithium containing salt are present directly between the solid polymer electrolyte layer, and the second silicon based electrode, wherein the second Li-salt containing conductive adhesive forms a first interface with the solid polymer electrolyte layer and the second Li-salt containing conductive polymeric adhesive forms a second interface with the second interfacial additive layer, and the second interfacial additive layer forms an interface with the counter electrode.

14. The device of claim 12 , wherein the second Li-salt containing conductive polymeric adhesive is composed of a polypyrrol (Ppy), polythiophene, polyaniline (PANI), polyphenylene sulfide, Ppy/carbon nanotube composites, poly(3-(potassium-4-butanoate) thiophene) (PPBT) and poly(ethylene glycol) (PEG) composites, and poly polystyrene sulfonate and carbon composites, and the second molten lithium containing salt is composed of at least one of lithium hexafluorophosphate, lithium perchlorate, lithium trifluoromethanesulfonate, lithium fluoride, LiBF 4 , lithium chloride, lithium phosphate compounds, lithium bromide compounds, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium difluoro(oxalato)borate (LiDFOB), or lithium bis(oxalato)borate(LiBOB).

15. The device of claim 1 , wherein an interfacial area between the silicon based electrode and a composite composed of the interfacial additive layer and the Li-salt containing polymeric adhesive has a charge resistance of less than 10 ohms/cm 2 , the interfacial area and bulk regions of the solid polymer electrolyte layer has a mass transport resistance of less than 33 ohm/cm 2 , and wherein a mass transfer/charge transfer resistance ratio is less than, or equal to, 3.5.

16. A device comprising:
a silicon based electrode composed of boron doped crystalline silicon;
an interfacial additive layer composed of molten lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), wherein the interfacial additive layer has a first surface forming an interface with a surface of the silicon based electrode;
a Li-salt containing conductive polymeric adhesive composed of a mixture of polyaniline (PANI) and LiTFSI forming an interface with a second surface of the interfacial additive layer that is opposite the first surface of the interfacial additive layer; and
a solid polymer electrolyte layer composed of a mixture of polycaprolactone, succinonitrile and LiTFSI forming an interface with the Li-salt containing conductive polymeric adhesive.

17. The device of claim 16 , further comprising a second Li-salt containing conductive polymeric adhesive composed of a mixture of polyaniline and LiTFSI forming an interface with the solid polymer electrolyte layer, a second interfacial additive layer composed of molten LiTFSI forming an interface with the second Li-salt containing conductive polymeric adhesive, and a second silicon based electrode composed of boron doped crystalline silicon forming an interface with the second interfacial additive layer.

18. A method of forming a device, the method comprising:
depositing a layer of a lithium containing salt on a surface of a silicon based electrode;
heatin

Assignees

• IBM

Inventors

• Collins John
• Afzali-Ardakani Ali
• Todorov Teodor K
• De Souza Joel P
• Sadana Devendra K

Classifications

• H01M50/497

  Ionic conductivity · CPC title

• H01M50/42

  Acrylic resins · CPC title

• H01M50/414

  Synthetic resins, e.g. thermoplastics or thermosetting resins · CPC title

• H01G11/50

  specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation · CPC title

• H01G4/18

  of synthetic material, e.g. derivatives of cellulose (H01G4/16 takes precedence) · CPC title