The cathode, or air electrode, is a thin porous layer on the electrolyte where oxygen reduction takes place. The overall reaction is written in Kroger-Vince Notation as follows:
Cathode materials must at a minimum, electronically conductive. Currently, lanthanum strontium manganese (LSM) is the cathode material of choice for commercial use because of its compatibility with doped zirconium electrolytes. Mechanically, it has a similar coefficient of thermal expansion to YSZ and thus limits stress build-up because of CTE mismatch. Also, LSM has low levels of chemical reactivity with YSZ which extends the lifetime of the materials. Unfortunately, LSM is a poor ionic conductor and so the electrochemically active reaction is limited to the triple
Cathode materials must at a minimum, electronically conductive. Currently, lanthanum strontium manganese (LSM) is the cathode material of choice for commercial use because of its compatibility with doped zirconium electrolytes. Mechanically, it has a similar coefficient of thermal expansion to YSZ and thus limits stress build-up because of CTE mismatch. Also, LSM has low levels of chemical reactivity with YSZ which extends the lifetime of the materials. Unfortunately, LSM is a poor ionic conductor and so the electrochemically active reaction is limited to the triple