Some innovative technologies using solid electrolytes in measuring gas compositions

Solid electrolytes have received considerable scientific attention and assumed important technological significance in recent years, due to potential practical applications in fuel cells, batteries, electrochromics, process control, sensors and environmental protection. Use of solid electrolytes for developing electrochemical gas sensors is a well established field with successful commercial applications related mainly to oxygen measurements. Discovery of new solid electrolytes have led to new areas of development and applications such as hydrogen monitoring. Applicability of solid electrolytes have also been extended to species which are not ionically mobile in the electrolyte by use of auxiliary phases. More recently, significant progress in sensing of molecular species such as CO₂, SO₂, SO₃, NO, NO₂, HCl, H₂O and HF have been achieved by interfacing 2 or more electrolytes in electrochemical chains and/or by using auxiliary phases, semi-permeable coatings or in-situ catalysts to promote the desired electrode reactions. Paper presented at the 4th Euroconference on Solid State Ionics, Renvyle, Galway, Ireland, Sept. 13–19, 1997