Abstract: To reduce the diffusion resistance, improve the energy efficiency and extend the life of solid oxide electrolysis cells (SOEC), the porosity and microstructure optimization of SOEC cathode support layer were studied. Polymethyl methacrylate(PMMA)was added into the cathode as an alternative of starch for pore formation. The experimental results show that the porosity of cathode reaches 45% with conductivity of 6726 S/cm when the PMMA content is 10wt%. The round micro-pores formed by PMMA are well distributed with an average diameter of about 10 μm, which not only significantly reduce the gas diffusion resistance and increase the mechanical strength of cathode materials, but also improve largely the electrolysis efficiency, stability and hydrogen production performance of the SOEC. After the microstructure modification and optimization of cathode layer, the hydrogen production rate of SOEC using PMMA pore former can reach 175mL/(cm²·h), which is 1.5 times of the hydrogen production rate of starch. Also their steam diffusion resistance reduce 50% at 850℃ and 1.3V electrolysis voltage, which indicates that PMMA is a very promising candidate for the application of SOEC technology.

Key words: solid oxide electrolysis cells(SOEC), nuclear hydrogen production, microstructure modification, cathode support layer, diffusion