Solid oxide fuel cells with (La,Sr)(Ga,Mg)O_3-δ electrolyte film deposited by radio-frequency magnetron sputtering

In this study, solid oxide fuel cells (SOFCs) containing a high quality La_0.9S_r0.1Ga_0.8Mg_0.2O_3-δ (LSGM) film deposited on anode supported substrate using RF magnetron sputtering are successfully prepared. The anode substrate is composed of two functional NiO/Sm_0.2Ce_0.8O_2-δ (SDC) composite layers with ratios of 60/40 wt% and 50/50 wt% and a current collector layer of pure NiO. The as-deposited LSGM film appears to be amorphous in nature. After post-annealing at 1000 °C, a uniform and dense polycrystalline film with a composition of La_0.87S_r0.13Ga_0.85Mg_0.15O_3-δ and a thickness of 3.8 μm is obtained, which was well adhered to the anode substrate. A composite LSGM/La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) layer, with a ratio of 30/70 wt%, is used as the cathode. The SOFC prepared reveals a good mechanical integrity with no sign of cracking, delamination, or discontinuity among the interfaces. The total cell resistance of a single cell with LSGM electrolyte film declines from 0.60 to 0.10 Ω cm² as the temperature escalates from 600 to 800 °C and the open circuit voltage (OCV) ranges from 0.85 to 0.95 V. The maximum power density (MPD) of the single cell is reported as 0.65, 1.02, 1.30, 1.42, and 1.38 W cm⁻² at 600, 650, 700, 750, and 800 °C, respectively. The good cell performance leads to the conclusion that RF magnetron sputtering is a feasible deposition method for preparing good quality LSGM films in SOFCs.