Heat-resistant electrolyte materials and electrochromic devices including them
The present disclosure relates to relates to heat-resistant gel electrolyte materials and their uses, for example, in electrochromic devices such as electrochromic windows. In certain embodiments, the disclosure provides an electrolyte material including a polymer of ethyleneimine, optionally at least partially crosslinked (e.g., with an epoxide crosslinker such as the diglycidyl ether of bisphenol A); a lithium salt (e.g., lithium perchlorate); and a high-boiling solvent (e.g., DMSO). The electrolyte materials can be used in electrochromic devices, such as electrochromic windows, e.g., for use as automobile sunroofs.
1. An electrolyte material comprising:
about 35 to about 65 wt % of a polymer of ethyleneimine having at least 90 wt % ethyleneimine subunits, the polymer being at least partially crosslinked with residues from a polyfunctional epoxide crosslinker in an amount of about 0.1 to about 4 wt %;
about 0.2 to about 5 wt % of a lithium salt; and
about 20 to about 64 wt % of a high-boiling solvent.
2. The electrolyte material according to claim 1 , wherein the polymer of ethyleneimine has a molecular weight in the range of about 1000 g/mol to about 100,000 g/mol.
3. The electrolyte material according to claim 1 , wherein the polymer of ethylene imine) is present in the electrolyte material in an amount in the range of about 40 wt % to about 60 wt %.
4. The electrolyte material according to claim 1 , wherein the polymer of ethyleneimine has at least about 95 wt % ethyleneimine subunits.
5. The electrolyte material according to claim 1 , wherein the polymer of ethyleneimine is poly(ethyleneimine).
6. The electrolyte material according to claim 1 , wherein the lithium salt is lithium perchlorate.
7. The electrolyte material according to claim 1 , wherein the lithium salt is present in the electrolyte material in an amount in the range of about 0.2 wt % to about 3 wt %.
8. The electrolyte material according to claim 1 , wherein the high-boiling solvent is DMSO.
9. The electrolyte material according to claim 1 , wherein the high-boiling solvent is present in an amount in the range of about 26 wt % to about 53 wt %.
10. The electrolyte material according to claim 1 , wherein the sum of the amounts of the high-boiling solvent, the polymer of ethyleneimine, the lithium salt and the crosslinking residues is at least about 80 wt % of the electrolyte material.
11. The electrolyte material according to claim 1 , consisting essentially of the high-boiling solvent, the polymer of ethyleneimine, the lithium salt, and the crosslinking residues.
12. The electrolyte material according to claim 1 , consisting essentially of DMSO, the polymer of ethyleneimine, lithium perchlorate and diglycidyl ether of bisphenol A.
13. An electrochromic device comprising
an electrochromic material;
a counterelectrode; and
the electrolyte material according to claim 1 disposed between the electrochromic material and the counterelectrode,
the counterelectrode being capable of electrochemically reversibly absorbing lithium ions from the electrolyte and releasing lithium ions into the electrolyte.
14. The electrochromic device according to claim 13 , wherein the electrochromic material, the counterelectrode and the electrolyte material are disposed between two bodies of transparent media.
15. The electrochromic device according to claim 13 , further comprising a voltage source operatively coupled to the electrochromic material and the counterelectrode.
16. The electrochromic device according to claim 13 , wherein the electrochromic material is a polythiophene and the counterelectrode is formed from V 2 O 5 —TiO 2 .
17. The electrochromic device according to claim 16 , configured as an automobile.
18. The electrolyte material according to claim 1 , having a % transmittance at 580 nm of at least about 50% per 100 μm thickness at 60° C.
19. An electrolyte material comprising:
a polymer of ethyleneimine;
a lithium salt; and
a high-boiling solvent,
the electrolyte material having a % transmittance at 580 nm of at least about 50% per 100 μm thickness at 60° C.
20. The electrolyte material according to claim 19 , wherein the polymer of ethyleneimine has at least about 90 wt % ethyleneimine subunits.
21. The electrolyte material according to claim 19 , wherein the sum of the amounts of the high-boiling solvent, the polymer of ethyleneimine, the lithium salt and any crosslinker or residues crosslinking the polymer of ethyleneimine is at least about 80 wt % of the electrolyte material.