PROPERTIES OF (La_1-xSr_x)₂(Ni_0.9Mn_0.1)O_4+δ BASED CATHODES

La₂NiO₄ (LNO) is a well-known K₂NiF₄ type oxide which has been suggested as a cathode for IT-SOFC due to the high electronic and ionic conductivity [1]. However the surface exchange of LNO is should still be improved in order for it to be used in practical applications. Recently 10% Mn and Sr substitution has been shown to increase the surface exchange in LNO [2]. However in order to stabilize the K₂NiF₄ structure the addition of manganese requires and addition of Sr as well. While a 1:1 ratio of the Sr-Mn seems to be stable, changing this ratio can change the oxidation state of Mn and Ni in the compound and as such change the fundamental properties of the compound. In this research the effect of changing the Sr-Mn ratio in (La_1-xSr_x)₂(Ni_1-yMn_y)O_4+δ compounds on the mixed conductivity, and surface exchange was determined. This was correlated to the change in the oxidation state of Mn and Ni in the compounds.

References

• J. Skinner, J.A. Kilner, Oxygen diffusion and surface exchange in La_2-xSr_xNiO_4+δ, Solid State Ionics, 135 (2000) pp. 709–712.
• Wenyuan Li, Bo Guan, Jianhua Yan, Nan Zhang, Xinxin Zhang, Xingbo Liu, Enhanced surface exchange activity and electrode performance of (La_2-2xSr_2x)(Ni_1-xMn_x)O_4-δ cathode for intermediate temperature solid oxide fuel cells, Journal of Power Sources, 318 (2016) pp.178-183