Perovskite lanthanum strontium manganite

To meet the requirements for electronic conductivity in both the SOFC anode and cathode, a metallic electronic conductor, usually nickel, is typically used in the anode, and a conductive perovskite, such as lanthanum strontium manganite (LSM), is typically used in the cathode. Because the electrochemical reactions in fuel cell electrodes can only occur at surfaces where electronic and ionically conductive phases and the gas phase are in contact with each other (Figure 6.1), it is common... 

Currently, the standard SOFCs use yttria-stabilized zirconia (YSZ) (see Section 2.4.3) containing typically 8 mol% of Y02 as the electrolyte, a ceramic metal (a cermet) composed of Ni plus YSZ as the anode, and lanthanum strontium manganite (LSM) perovskite (La Sr, MnO,, ) as the cathode material [5,7,9,135],... 

Jiang SP (2008) Development of lanthanum strontium manganite perovskite cathode matraials of solid oxide fuel cells a review. J Mater Sci 43 6799-6833... 

The oxygen reduction reaction occurs at the cathode. Nearly all candidate cathode materials are based on perovskite oxides such as lanthanum strontium manganite (LSM). However, the oxygen reduction reaction is particularly affected by lower operating temperatures with kinetics and transport processes that are thermally activated. The development of materials with higher electrochemical activities for the oxygen reduction reaction is critical for the development of IT-SOFCs with higher efficiencies. 

Anode - Reaction site for oxidation of water (creation of O2) - Porous layer (to facilitate the evacuation of the gas produced) - Perovskite-type oxide - The materials typically used are LSM (LaSrxMni.x03) or LSCF - Many other alternatives are possible - LSM = Lanthanum strontium manganite -LSCF = Lanthanum cobalt strontium ferrite... 

Zvdtora, P. et al (2013) Influence of surface and finite size effects on the structural and magnetic properties of nanocrystalline lanthanum strontium perovskite manganites. /. Solid State Chem., 204, 373-379. 

Baythoun, M. S. G Sale, F. R. 1982. Production of strontium-substituted lanthanum manganite perovskite powder by the amorphous citrate process. /. Mat. Sci. 17 2757-2769. 

The favoured material is modified lanthanum manganite (e.g. La0 8Sr0 2Mn03+x) which has the perovskite structure. It is a p-type semiconductor the electron transport occurring by electron-hopping (see Section 2.6.2) between the +3 and +4 states of the Mn ion. The strontium-doping enhances the conductivity. 

Yang, C.K., Yamazaki, Y., Aydin, A., and Haile, S.M. (2014) Thermodynamic and kinetic assessments of strontium-doped lanthanum manganite perovskites for two-step thermochemical water splitting. 

Baythoun M.S.G., Sale F.R. Production of strontium-substituted lanthanum manganite perovskite powder by the amorphous citrate process. J. Mater. Sci. 1982 17 2757-2769 Bernard M.I.B., Soledade L.E., Santos I.A., Leite E.R., Longo E., Varela J.A. Influence of the concentration of 86203 and the viscosity of the precursor solution on the electrical and optical properties of Sn02 thin films produced by the Pechini method. Thin Solid Films 2002 405 228-233... 

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