An industrial mixed rare-earth oxide fuel cell with low cost and high electrochemical performance

Abstract

Rare-earth oxides determine the commercialization and development of solid oxide fuel cells (SOFCs) for all the types, still remining challenges of high cost and low electrochemical performance. Here, we propose an industrial mixed rare-earth oxide fuel cell using the state-of-the-art industrial lanthanum-praseodymium-cerium (La-Pr-Ce, LCP) oxide electrolyte as a proof-of-concept, achieving low-cost and high electrochemical performance. The rare-earth oxides, La2O3, CeO2, PrO2 and LCP are prepared and studied by oversimplified solid reaction experiments with density functional theory (DFT) calculations. The LCP is simplified as La, Pr doped CeO2, in which the effects of rare-earth elements doping are concluded as follows: firstly, the Ce4+/Ce3+ redox pairs can be slightly suppressed by La, Pr co-doping; secondly, the bandgap of LCP is decreased to 2.01 eV with enhanced electron conductivity of 7.4 × 10−5 S cm−1, which may originate from Pr-doping. The power density output of industrial mixed rare-earth oxide fuel cells with La2O3, CeO2, PrO2 and LCP electrolytes achieve 630 mW cm−2, 639 mW cm−2, 469 mW cm−2 and 797 mW cm−2 at 500 °C, respectively, indicating that the LCP electrolyte presents ascendant performance output with the ionic conductivity of 0.248 S cm−1. The industrial mixed rare-earth oxide fuel cells not only broaden the exploit avenue for industrial mixed rare-earth oxides, but also unravel the roadblock for the industrialization of SOFCs at low temperatures below 500 °C.