The most important requirements to electrodes for solid oxide fuel cells an
d similar devices are listed, and it is explained how the requirements usua
lly lead to a composite electrode. Three examples of composite electrodes a
re described in some details, namely the ceria based hydrogen electrode, th
e Ni-YSZ cermet anode and the LSM-YSZ. Here YSZ means yttria stabilized zir
conia, and LSM is lanthanum strontium manganate.