Xiaomao Sun 1, Jin Lin 2, Xuetao Xing 2, Jinbo Gong 1, You Zhou 3, Shujun Mu 3, Changjun Liu 4, Xingyong Liu 1, Qiang Hu 1,5
(1.School of Chemical Engineering, Sichuan University Of Science & Engineering, Zigong 643000, China; 2. Department of
Electrical Engineering, Tsinghua University, Beijing 100084, China; 3. National Institute of Clean and low carbon energy, Beijing
102211, China; 4. School of Chemical Engineering, Sichuan University, Chengdu 610065, China; 5. Sichuan Energy Internet
Research Institute, Tsinghua University, Chengdu 610000, China)
Abstract: Solid electrodes are of importance to fabricate solid oxide cells for high efficiency energy conversion and emission control purpose. Oxide electrodes are widely studied for solid oxide fuel cells (SOFCs) and electrolysis cells (SOECs), though their reliability are not fully satisfactory at elevated temperature. On the other hand, the composite electrodes made of platinum and yttria stabilized zirconia (YSZ) have been widely used in oxygen and nitrogen oxides (NOx) sensors for emission control, showing satisfactory endurance under harsh conditions. The normal Pt/YSZ electrodes contains relatively high Pt content, meaning higher material cost. The study thus aims at developing a three-component solid electrode consisting of platinum, 10 mol% gadolinia doped ceria (GDC10) and 5 mol% yttria stabilized zirconia (5YSZ), which can realize reduced both polarization resistance and platinum load, compared to the binary electrodes of Pt/YSZ. In these three-component electrodes, 5YSZ in electrode can enhance the contact with 5YSZ based electrolyte and the optimal ratio of Pt/5YSZ/GDC10 is 1 : 1 : 1. The platinum load can be further reduced by properly introducing graphite while even lower electrode resistance can be reached. The optimal graphite content lies in the range of 10-30wt%. Electrode impregnation improve electrode performance remarkably. The impregnated electrode in general is more sensitive to temperature change with the activation energy of 100-120 kJ·mol-1. The co-fired electrode along with electrolyte has slightly higher resistance compared to its separately fired counterpart.
Key words: platinum; solid electrode; solid oxide cell; yttria stabilized zirconia; ceria.