OPTICALLY TRANSPARENT POLYMERIC ION CONDUCTIVE LAYERS FOR ELECTROCHROMIC DEVICES
Polymeric ion conductive layers and electrochromic devices utilizing the same are described. The polymeric ion conductive layer may include a polymer having a Shore hardness of greater than 80A, an electrolyte dispersed in the polymer, and a plasticizer dispersed in the polymer. The polymeric ion conducive layer may have no creep at elevated temperatures. The polymeric ion conductive layer may have an ionic conductivity of greater than or equal to about 1E-5 S/cm, a haze of less than 3%, and a light transmission of greater than or equal to about 80%. An electrochromic device may include a first optically transparent layer, a second optically transparent layer, and electrochromic layers including the polymeric ion conductive layer interposed between the first and second optically transparent layers.
1 . A polymeric ion conductive layer for an electrochromic device, comprising:
a polymer comprising a Shore hardness of greater than 80 A;
an electrolyte dispersed in the polymer; and
a plasticizer dispersed in the polymer.
2 . The polymeric ion conductive layer of claim 1 , wherein the polymeric ion conductive layer comprises no creep as measured at about 85° C.
3 . The polymeric ion conductive layer of claim 1 , wherein the polymer comprises a Shore hardness of greater than 87 A.
4 . The polymeric ion conductive layer of claim 1 , wherein the polymer comprises a Shore hardness of greater than or equal to 55 D, greater than or equal to 60 D, greater than or equal to 67 D, greater than or equal to 72 D, or greater than or equal to 80 D.
5 . The polymeric ion conductive layer of claim 1 , wherein the polymeric ion conductive layer exhibits no creep as measured at about 85° C. for at least 24 hours.
6 . The polymeric ion conductive layer of claim 1 , wherein the polymeric ion conductive layer comprises an ionic conductivity of greater than or equal to about 1E-5 Siemens/cm (S/cm), greater than or equal to about 3.5E-5 S/cm, greater than or equal to about 4E-5 S/cm, greater than or equal to about 1E-4 S/cm, greater than or equal to about 2E-4 S/cm, or greater than or equal to about 3E-4 S/cm.
7 . The polymeric ion conductive layer of claim 1 , wherein the polymeric ion conductive layer comprises a light transmission, as measured according to reference test ASTM-D1003, of greater than or equal to about 80%.
8 . The polymeric ion conductive layer claim 1 , wherein the polymeric ion conductive layer comprises a haze, as measured according to reference test ASTM-D1003, of less than 3% or less than 2%.
9 . The polymeric ion conductive layer of claim 1 , wherein the polymeric ion conductive layer comprises a peel strength of greater than 25 N/mm, as measured according to ASTM D3167.
10 . The polymeric ion conductive layer of claim 1 , wherein the polymer comprises a thermoplastic polyurethane.
11 . The polymeric ion conductive layer of claim 10 , wherein the thermoplastic polyurethane comprises one or more aliphatic polyether thermoplastic polyurethanes.
12 . The polymeric ion conductive layer of claim 1 , wherein the electrolyte comprises a lithium salt.
13 . The polymeric ion conductive layer of claim 12 , wherein the lithium salt comprises one or more of lithium chloride (LiCl), lithium fluoride (LiF), lithium iodide (LiI), lithium nitrate (LiNO 3 ), lithium perchlorate (LiClO 4 ), lithium tetrafluoroborate (LiBF 4 ), lithium hexafluorophosphate (LiPF 6 ), lithium hexafluoroarsenat (V) (LiAsF 6 ), lithium triflate, lithium imide, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt, lithium 2-trifluoromethyl-4,5-dicyanoimidazolide (LiTDI), or a combination thereof.
14 . The polymeric ion conductive layer of claim 1 , wherein the plasticizer is present in an amount of greater than or equal to about 40 wt %, based on the total weight of the polymeric ion conductive layer.
15 . The polymeric ion conductive layer of claim 1 , wherein the plasticizer is present in an amount of greater than or equal to about 45 wt % to about 65 wt %, based on the total weight of the polymeric ion conductive layer.
16 . The polymeric ion conductive layer of claim 1 , wherein a difference between a Hansen Solubility Parameter of the polymer and a Hansen Solubility Parameter of the plasticizer is less than or equal to about 5.
17 . The polymeric ion conductive layer of claim 1 , wherein a difference between a Hansen Solubility Parameter of the polymer and a Hansen Solubility Parameter of the plasticizer is less than or equal to about 3.8.
18 . The polymeric ion conductive layer of claim 1 , wherein the plasticizer comprises one or more of propylene carbonate, ethylene carbonate, triethylene glycol bis(2-ehtylhexanoate) (TEG-EH), or any combination thereof.
19 . The polymeric ion conductive layer of claim 18 , wherein the plasticizer comprises:
a combination of propylene carbonate and triethylene glycol bis(2-ehtylhexanoate) (TEG-EH); or
a combination of ethylene carbonate, propylene carbonate, and triethylene glycol bis(2-ehtylhexanoate) (TEG-EH).
20 . An electrochromic device, comprising a first optically transparent layer, a second optically transparent layer, and electrochromic layers interposed between the first and second optically transparent layers, wherein the electrochromic layers comprise the polymeric ion conductive layer of claim 1 .