Optical Efficiency of the Electrochromic Windows Based on Solid Polymer Electrolytes
- PDF / 570,438 Bytes
- 13 Pages / 420.48 x 639 pts Page_size
- 85 Downloads / 189 Views
OPTICAL EFFICIENCY OF THE ELECTROCHROMIC WINDOWS BASED ON SOLID POLYMER ELECTROLYTES
M. Shabrang and D.P. Murray
Dow Chemical Company, Central Research, Catalysis Laboratory, Midland, Michigan 48674
ABSTRACT
Interest in the electrochromics research in the 80's was mainly directed towards potential applications for variable light transmission windows. Even though large-area electrochromic cells incorporating liquid electrolytes are being investigated, we focused on solid state devices. Such devices offer fewer fabrication problems in large-area applications. The solid electrolyte layer is a key component in the fabrication of the solid state windows. This layer must be transparent, electrochemically stable and display adequate ionic conductivity. Optical efficiencies of asymmetric solid state devices based on tungsten oxide as the electrochromic material and commercially available ionomers and polyelectrolytes - Naflon, poly(styrene sulfonic acid), and poly(2-acrylamido-2-methylpropanesulfonic acid), as the solid electrolyte layer are presented at room temperature and 90 C. Impedance behavior of this asymmetric system is discussed and compared with the behavior observed in other systems.
INTRODUCTION
Electrochromics is now considered as one of the more active areas of research in electrochemistry. In late 60's and 70's researchers were mostly interested in electrochromics with the Idea of using it in displays, such as watches, etc.. As it has been pointed out earlier (1), many aspects of the electrochromics materials and device concepts were neglected due to the focus on the high speeds in the early 70's. In the 80's and 90's the electrochromics are being researched with the concept of Variable Light Transmission (VLT) in mind. This concept is driven by a desire for energy savings, as well as increased levels of comfort in automobiles and residences. These goals are spelled out in
Mat. Res. Soc. Symp. Proc. Vol. 210. 01991 Materials Research Society
44
publications by major glass concerns and by the DOE-sponsored research organizations (2-4). Many issues related to large size windows led us to focus primarily on the solid electrolyte component of the electrochromic window as the key to a commercially viable large size system. Some of these issues are scalability, which dictates simple fabrication procedures; and safety, which discourages use of liquid based systems. In this paper we will focus attention on some preliminary results obtained on the solid electrolyte component of an electrochromic cell. The fundamental design which we use here for the arrangement of the device layers has been considered before. This design is the "asymmetricdesign"or "designA" as it is referred to in the electrochromics literature and which one encounters in Deb's original invention (5), and elsewhere (1,3,6,7). The asymmetric design not only is a functional design capable of forming a self-contained electrochromic window on its own, but also has the potential to be able to incorporate additional layers where the counter elec
Data Loading...
