Page 62 - High Temperature Solid Oxide Fuel Cells Fundamentals, Design and Applications

40 High Temperature Solid Oxide Fuel CeIls: Fundamentals, Design and Applications

pure hydrogen by using anodes, depolarised by another reducing cheap gas
and described the idea of gas production by internally short-circuited solid oxide
cells [ 12 41.
Activities in associated SOFC technologies helped in testing new materials,
designs and fabrication methods. An example was plasma spraying of complete
cells on an aluminium mandrel which was removed by leaching in a KOH
solution before high-temperature sintering [ 1231. For applications in fuel
cells, electrolysers, gas separators and chemical reactors, many proposals
for series connection of tubular solid oxide cells were also made at this time
(Figure2.11 [125]).

Figure2.11 Proposals forconnectingself-supporting tubularsolidelectrolytecellsin series (I 974).

2.5 On the Path to Practical Solid Oxide Fuel Cells
By 19 70 the results of investigations on properties and applications of solid oxide
electrolytes were so numerous as to make them very difficult to survey. A
comprehensive review by Etsell and Flengas included 6 74 references [ 12 61. But
commercial activity was confined to potentiometric oxygen sensors . In the USA,
the programme for development of SOFCs ran out in 19 70. The greatest obstacles