Industrial grade rare-earth triple-doped ceria applied for advanced low-temperature electrolyte layer-free fuel cells

In this study, the mixed electron-ion conductive nanocomposite of the industrial-grade rare-earth material (La³⁺, Pr³⁺ and Nd³⁺ triple-doped ceria oxide, noted as LCPN) and commercial p-type semiconductor Ni_0.8Co_0.15Al_0.05Li-oxide (hereafter referred to as NCAL) were studied and evaluated as a functional semiconductor-ionic conductor layer for the advanced low temperature solid oxide fuel cells (LT-SOFCs) in an electrolyte layer-free fuel cells (EFFCs) configuration. The enhanced electrochemical performance of the EFFCs were analyzed based on the different semiconductor-ionic compositions with various weight ratios of LCPN and NCAL. The morphology and microstructure of the raw material, as-prepared LCPN as well the commercial NCAL were investigated and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive X-ray spectrometer (EDS), respectively. The EFFC performances and electrochemical properties using the LCPN-NCAL layer with different weight ratios were systematically investigated. The optimal composition for the EFFC performance with 70 wt% LCPN and 30 wt% NCAL displayed a maximum power density of 1187 mW cm⁻² at 550 °C with an open circuit voltage (OCV) of 1.07 V. It has been found that the well-balanced electron and ion conductive phases contributed to the good fuel cell performances. This work further promotes the development of the industrial-grade rare-earth materials applying for the LT-SOFC technology. It also provides an approach to utilize the natural source into the energy field.