Study on the key materials for realizing electrolyte-free fuel cell and semiconductor-ionic membrane fuel cell

Electrolyte-free fuel cell (EFFC), which contains only a single layer of the composition of ionic conductor and electronic conductor, has been reported to accomplish the function of a traditional three-layer solid oxide fuel cell (SOFC). It is interesting that the electronic conductors used in the reported EFFCs usually contain elements like Li and Na. In this study, we try to find out the key issues of realizing EFFC and uncover its working mechanism. Based on a typical EFFC that is made with ionic conductor Ce0.8Sm0.2O1.9 (SDC) and electronic conductor Ni0.8Co0.15Al0.05LiO2-δ (NCAL), different types of EFFCs are constructed using SDC and the online decomposition products of NCAL during fuel cell operation. The key components for realizing the function of EFFC as well as the influence of these components on cell performance is studied. By applying semiconductor-ionic conductor (SIC) composite on both sides of the EFFCs for the purpose of improving the catalytic activity, semiconductor-ionic membrane fuel cell (SIMFC) is obtained, which exhibited enhanced performance. The critical issues for optimizing the power output and durability of EFFC and SIMFC are investigated. This work helps to understand the working mechanism of EFFC and SIMFC, and also provides insights into the optimization of these low-temperature fuel cells.