You're thinking of the Argonne research from Jan, that used iridium to create a closed lithium air battery. They used the iridium to prevent lithium peroxide from forming and clogging the pores of the electrode.
http://www.anl.gov/articles/stable-superoxide-opens-door-new...
This research from MIT is entirely different. It doesn't use iridium at all.
It's actually quite interesting how they solved this problem (in comparison to Argonne's approach). To quote the press release:
The secret to the new formulation is creating minuscule particles, at the nanometer scale (billionths of a meter), which contain both the lithium and the oxygen in the form of a glass, confined tightly within a matrix of cobalt oxide. The researchers refer to these particles as nanolithia. In this form, the transitions between LiO2, Li2O2, and Li2O can take place entirely inside the solid material, he says.
The nanolithia particles would normally be very unstable, so the researchers embedded them within the cobalt oxide matrix, a sponge-like material with pores just a few nanometers across. The matrix stabilizes the particles and also acts as a catalyst for their transformations.
http://news.mit.edu/2016/new-lithium-oxygen-battery-greatly-...
http://li.mit.edu/Archive/Papers/16/Zhu16KushimaNatureEnergy...