Electrochromic multi-layer devices with cross-linked ion conducting polymer
Multi-layer electrochromic structures, and processes for assembling such structures, incorporating a cross-linked ion conducting polymer layer that maintains high adhesive and cohesive strength in combination with high ionic conductivity for an extended period of time, the ion conducting polymer layer characterized by electrochemical stability at voltages between about 1.3 V and about 4.4 V relative to lithium, lithium ion conductivity of at least about 10 −5 s/cm, and lap shear strength of at least 100 kPa, as measured at 1.27 mm/min in accordance with ASTM International standard D1002 or D3163.
1. An electrochromic multi-layer stack, comprising:
a first substrate and a second substrate, each having a transparent conductive layer on at least one surface;
an electrochromic electrode and an electrochromic counter electrode in contact with the transparent conductive layers;
a cross-linked lithium-ion conducting polymer layer between the first electrochromic electrode and the electrochromic counterelectrode; and
wherein, at room temperature, the cross-linked ion conducting polymer (i) is electrochemically stable at voltages between about 1.3 V and about 4.4 V relative to lithium, (ii) has a lithium ion conductivity of at least about 10 −5 S/cm, and (iii) has a lap shear strength of at least 100 kPa, as measured at 1.27 mm/min in accordance with ASTM International standard D1002 or D3163.
2. The electrochromic multi-layer stack of claim 1 wherein the cross-linked ion conducting polymer has an electrochemical stability at voltages between about 1.3 V and about 4.0 V relative to lithium.
3. The electrochromic multi-layer stack of claim 1 , wherein the cross-linked ion conducting polymer has an ionic conductivity at room temperature of at least about 10 −2 S/cm.
4. The electrochromic multi-layer stack of claim 1 , wherein the cross-linked ion conducting polymer has a lap shear strength in the range of about 200 kPa to 600 kPa.
5. The electrochromic multi-layer stack of claim 1 , wherein the cross-linked ion conducting polymer is elastically deformable and has an elongation to failure of at least 1 mm.
6. The electrochromic multi-layer stack of claim 1 , wherein the cross-linked ion conducting polymer has a glass transition temperature (Tg) in the range of about −5° to about −40° C.
7. The electrochromic multi-layer stack of claim 1 , wherein the first and second substrates comprise glass including a tempered carrier glass.
8. A process for manufacturing an electrochromic multi-layer stack, the process comprising:
(A) depositing an ion conducting polymer feedstock onto a first substrate comprising a first transparent conductive layer and a first electrode layer,
(B) laminating a second substrate comprising a second transparent conductive layer and a second electrode layer to the first substrate to form an electrochromic multi-layer stack comprising, in succession, the first substrate, the first transparent conductive layer, the first electrode layer, the ion conducting polymer feedstock layer, the second electrode layer, the second transparent conductive layer, and the second substrate; and
(C) irradiating the electrochromic multi-layer stack to polymerize the ion conducting polymer feedstock, forming a cross-linked ion conducting polymer layer, wherein the cross-linked ion conducting polymer, at room temperature, (i) is electrochemically stable at voltages between about 1.3 V and about 4.4 V relative to lithium, (ii) has a lithium ion conductivity of at least about 10 −5 S/cm, and (iii) lap shear strength of at least 100 kPa, as measured at 1.27 mm/min in accordance with ASTM International standard D1002 or D3163.
9. The process of claim 8 , wherein depositing the ion conducting polymer feedstock comprises dispensing the ion conducting polymer feedstock from a nozzle at room temperature having a viscosity of about 20,000 cP to about 50,000 cP.
10. The process of claim 8 , wherein forming a cross-linked ion conducting polymer comprises cross-linking the ion conducting polymer to an extent to have a lap shear strength of at least about 200 kPa.
11. The process of claim 8 , wherein forming a cross-linked ion conducting polymer comprises cross-linking the ion conducting polymer to an extent to be elastically deformable and still maintain mechanical strength.
12. The process of claim 8 , wherein forming a cross-linked ion conducting polymer comprises cross-linking the ion conducting polymer to have an elongation to failure of at least 1 mm.