Current status of proton-conducting solid oxide fuel cells development

Abstract

Solid oxide fuel cells (SOFC) are promising devices for high efficiency cogeneration. The most widely used and studied ones have an anion conducting electrolyte that requires high operating temperatures to limit ohmic losses across this electrolyte; temperatures typically range between 800 and 1,000°C. This temperature is associated with undesirable phenomena such as material interaction and insulating phase formation that result in unsatisfactory durability and high cost for market entry. Proton conducting solid oxide fuel cells (PCFC) constitutes a promising alternative since they allow a significant decrease in operating temperature. The Ba(Zr,Ce,Ln)O 3-d perovskite family exhibits ionic conductivities reaching 10 -2 to 10 -1 S cm -1 at temperatures as low as 600-700°C, these values being obtained with anion conducting SOFC between 700 and 1,000°C. On the basis of a review of work on half cells and complete cells, this paper addresses the main parameters that control and limit PCFC behaviour. This analysis aims at proposing recommendations for designing and testing proton conducting fuel cells.

Fundamentals of electro- and thermochemistry in the anode of solid-oxide fuel cells with hydrocarbon and syngas fuels

“…10), e.g., La 1−x Sr x Ga 1−y Mg y O 3−(x+y)/2 (LSGM)-based perovskites; La 2 Mo 2 O 9 (LAMOX); Bi 4 V 2−x M x O 11−y (BIMEVOX); several pyro-chlores with relatively high ionic transport, such as (Gd,Ca) 2 Ti 2 O 7−δ ; apatite materials derived from Ln 10−x Si 6 O 26±δ , where Ln represents a lanthanideseries element, collectively known as rare-earth elements; 16 as well as proton-conducting materials, which allow for a significant decrease in operating temperature while improving performance. 22 Moreover, gadolinia-doped ceria (GDC), samaria-doped ceria (SDC), and other ceria-based electrolytes have received a great deal of attention because of their ability to conduct oxygen ions at lower temperatures than YSZ. [23][24][25][26][27] The cathode in SOFCs is usually composed of porous perovskite materials, which are oxides characterized by relatively good electronic conduction at high temperatures in an oxidizing atmosphere.…”

Strategies for Lowering Solid Oxide Fuel Cells Operating Temperature

“…Although not discussed in the present work, SOFCs based on proton conducting electrolytes, instead of oxide ionic conductors, are of particular interest because they constitute a promising alternative at the intermediate-to-low range of temperatures still far from being introduced into commercial SOFCs because of stability problems and still low performances. For a detailed discussion on the applicability of proton conducting materials in SOFC refer to [47] and [48].…”

Investigation of the structural and electrical properties of Co-doped BaCe0.9Gd0.1O3−δ

“…However, their high operation temperature (800-1000°C), which is requisite in order to limit the ohmic losses across the electrolyte in the case where anion conducting electrolytes are used [4], hinders their long term stability and durability, increasing at the same time the cost for market entry.…”