Research On Failure Mechanism Of Electrolyte Materials Of Solid Oxide Fuel Cells

Solid Oxide Fuel Cell(SOFC)is a new type of energy use that is environmentally friendly and has a high energy conversion rate.At the current application of fuel cell,SOFC electrolyte material is very prone to bending and cracking as an ultra-thin brittle ceramic material,which has a very adverse effect on the service life and overall performance of SOFC.At present,most of the research on SOFC electrolyte materials in engineering focus on its electrical properties,not the mechanical properties and failure mechanism of emerging materials.The research on the mechanism of microscopic structure failure is rarely reported.In this paper,the SOFC electrolyte material plate samples were prepared experimentally,and the mechanical properties were determined.The fracture properties of the microscopic structure were simulated by the finite element method.The mechanical properties and fracture mechanism of the materials were systematically studied.In addition,Ce O2 based electrolyte material Ce0.80Sm0.2 O2-δ(CSO)doped with 20% Sm3+ was selected as the research object.The transition metal Cu2+ was doped and the transition metal Cu2+ was doped to synthesize Ce0.79Cu0.01Sm0.2O2-δ(CSCO).The PVA-assisted combustion method was used to prepare the disc samples of the two materials,and the relative density study,SEM analysis and biaxial bending experiments were carried out,and the compactness and mechanical properties of the sintered compacts before and after doping were compared.Finally,the microscopic structure of the SOFC electrolyte material is investigation using the Voronoi grid method with reference to the microstructure of the actual electrolyte material.The cohensive element method is used for simulating the fracture of the microstructure.Through the constitutive relationship of each component of the microscopic crystal model,the parameters of each component of the microscopic crystal structure were adjusted to simulate the fracture mode of the microscopic crystal structure under the grain boundary strengthening theory.Based on this model,the influence of the existence of pores on the fracture mode of the microscopic crystal structure was investigated by inserting pores in the microscopic crystal structure.By comparing with the experimental results,the fracture toughness of microscopic crystal structure is mainly controlled by the grain boundary and the material properties inside the crystal.