R-P type layered medium-entropy perovskite structure cathode material and preparation method thereof

Abstract

The molecular formula of the R-P type layered medium-entropy perovskite structure cathode material is La < 1.4 > Sr < 0.6 > (Co, Fe, Ni, Mn) < 1 / 4 > O < 4 + delta >, and delta represents the oxygen vacancy content. The preparation method comprises the following steps: taking compounds respectively containing La < 3 + >, Sr < 2 + >, Co < 2 + >, Fe < 3 + >, Ni < 2 + > and Mn < 2 + > as raw materials, weighing the raw materials according to the stoichiometric ratio of corresponding elements in the molecular formula, respectively adding the raw materials into deionized water, stirring, dissolving and uniformly mixing to obtain a solution A; respectively adding citric acid and ethylene glycol into the solution A, heating, stirring and dissolving, transferring into an electric furnace, heating until spontaneous combustion, and continuously heating until ash is formed by combustion, so as to obtain a precursor; and grinding the precursor, transferring the ground precursor into a muffle furnace, and heating to obtain cathode powder, namely the R-P type layered medium-entropy perovskite structure cathode material. The method can improve the stability and conductivity of the cathode material and reduce the thermal expansion coefficient of the cathode material.

Description

technical field [0001] The invention belongs to the technical field of medium and low temperature SOFC cathode materials, in particular to an R-P type layered medium entropy perovskite structure cathode material and a preparation method thereof. Background technique [0002] Solid oxide fuel cells (SOFCs) are considered to be one of the most promising energy conversion and storage devices, while conventional SOFCs require higher operating temperatures to achieve better results, which in turn affect the electrode Materials, connecting materials, etc. put forward more stringent requirements, resulting in limited stability and service life of solid oxide fuel cells. However, SOFC is faced with problems such as large cathode polarization impedance and serious electrode loss under the operating environment of medium and low temperature. Therefore, it is proposed to develop materials with higher ionic-electronic conductivity (MIEC) as cathodes to promote the oxygen reduction reac...

AI Technical Summary

Problems solved by technology

Chinese patent CN105449227A discloses a layered perovskite fuel cell cathode material and its preparation method. The chemical formula of the cathode material is Ln 0.5-1.5 Ba 0.5-1.5 mn 0.5-2 Mg 0.05-0.2 co 0.5-2 o 5+δ , belongs to the B-site ternary new layered perovskite oxide. Although the thermal expansion and electrochemical performance of the cathode material have been improved, the material will undergo structural transformation when sintered for a long time above 700 ° C, and its stability is poor.

However, simultaneous doping at the A and B sites to form an R-P type mid-entropy perovskite oxidation has not been reported so far.

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