Hello.  Yttria stabilized Zirconia (YSZ) is a typical solid electrolyte in fuel cells.  Cheers.

You may wanna follow Dr. S. Nonnenmann at

https://www.researchgate.net/profile/Stephen_Nonnenmann

Solid ceramic electrolyte, such as zirconium oxide stabilised with yttrium oxide.

Thanks a lot  friends:)

you can use thin film of Nafion within 25 micrometer as polymer electrolyte membrane for Fuel Cell. Also you can use Aquivion.

10 micrometer thick film of YSZ or CGO on 1-2 mm anode subststrate  is used for the SOFC application.  

For polymer electrolyte membrane fuel cells Nafion membranes have been the standard so far.. However, many innovations and modifications are being carried out.. You can check these publications.. May be you will find them useful.. Best of luck..

http://www.sciencedirect.com/science/article/pii/S0376738814007030

http://www.sciencedirect.com/science/article/pii/S0376738814004256

http://www.sciencedirect.com/science/article/pii/S0306261914002050

http://www.sciencedirect.com/science/article/pii/S0306261913010283

http://www.tandfonline.com/doi/abs/10.1080/15583724.2013.839566

http://www.sciencedirect.com/science/article/pii/S0306261913005965