Low vapor pressure solvent for electrochromic devices

• US 8,988,757 B2
• Filed: 10/27/2004
• Issued: 03/24/2015
• Est. Priority Date: 03/12/2004
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Weidner, Arthur P.
• Primary Examiner(s): WILKES, ZACHARY W
• Application Number:
  US10/974,088
• Publication Number:
  US 20050200933A1
• Time in Patent Office: 3,800 Days
• Field of Search: 359/270, 359/265
• US Class Current: 359/273
• CPC Class Codes: B64C 1/1484 Windows B64C1/1492 takes precedence
• CPC Class Codes: B64D 2011/0061 Windows displaying outside view, artificially generated
• CPC Class Codes: G02F 1/1506 caused by electrodeposition, e.g. electrolytic deposition of an inorganic material on or close to an electrode
• CPC Class Codes: G02F 1/1516 comprising organic material
• CPC Class Codes: G02F 1/15165 Polymers
• CPC Class Codes: G02F 1/1525 characterised by a particular ion transporting layer, e.g. electrolyte
• CPC Class Codes: G02F 1/153 Constructional details
• CPC Class Codes: G02F 1/1533 structural features not otherwise provided for
• CPC Class Codes: G02F 1/163 Operation of electrochromic cells, e.g. electrodeposition cells; Circuit arrangements therefor
• CPC Class Codes: G02F 2001/164 the electrolyte is made of polymers

Abstract

The present invention provides an electrolyte for electrochromic devices, the substance comprising γ-butyrolactone (gamma-butyrolactone or GBL). The electrolyte may include polymethylmethacrylate. The electrolyte may further include a salt, such as a salt that includes lithium perchlorate or trifluorosulfonimide. In accordance with further aspects to the invention, the electrolyte may include propylene carbonate.

Claims

1. An electrolyte for transmitting ions for an electrochromic device, the electrolyte comprising:

a solvent including propylene carbonate, and from 60% to 90% by weight of gamma-butyrolactone; and

at least one salt, wherein the at least one salt includes lithium trifluorosulfonimide.

2. The electrolyte of claim 1, wherein the electrolyte further comprises a polymer matrix.

3. The electrolyte of claim 2, wherein the polymer matrix includes polymethylmethacrylate.

4. The electrolyte of claim 2, wherein the at least one salt includes lithium perchlorate.

5. The electrolyte of claim 1, wherein the at least one salt further includes lithium perchlorate.

6. An electrochromic device comprising:

a first electrode sheet, the first electrode sheet being substantially transparent;

a second electrode sheet, the second electrode sheet being substantially transparent;

an electrochromic polymer layer disposed between the first electrode sheet and the second electrode sheet; and

a gel electrolyte disposed between the electrochromic polymer layer and one of the first electrode sheet and the second electrode sheet, the gel electrolyte including lithium trifluorosulfonimide and 60% to 90% by weight of gammabutyrolactone.

7. The electrochromic device of claim 6, wherein the gel electrolyte includes polymethylmethacrylate.

8. An aircraft comprising a fuselage and a window assembly in the fuselage, the window assembly including a frame adapted to hold the electrochromic device of claim 6.

9. An aircraft window comprising a frame adapted to hold the electrochromic device of claim 6, wherein the first electrode sheet, the second electrode sheet, the electrochromic polymer layer, and the gel electrolyte function as a window shade for an aircraft window.

10. The electrochromic device of claim 6, wherein the electrochromic layer includes a plurality of pigments.

11. The electrochromic device of claim 6, wherein the gel electrolyte includes approximately 70% by weight of gamma-butyrolactone, 20% by weight propylene carbonate, 3% by weight lithium perchlorate, and 7% by weight polymethylmethacrylate.

12. An electrochromic device, comprising:

an electrolyte having propylene carbonate, and trifluorosulfonimide dissolved in an effective amount of gamma-butyrolactone, wherein the effective amount includes from 60% to 90% gamma-butyrolactone by weight, inclusive.

13. The electrochromic device of claim 12, wherein the effective amount includes from 65% to 75% gamma-butyrolactone by weight, inclusive.

14. The electrochromic device of claim 12, further comprising a plurality of pigments of electrochromic material.

15. The electrochromic device of claim 14, further comprising first and second electrode sheets disposed on opposing sides of the electrolyte.

16. The electrochromic device of claim 15, wherein at least one of the first and second electrode sheets comprises a tinted electrode sheet.

17. The electrochromic device of claim 14, wherein the electrolyte includes polymethylmethacrylate.