Natural Mineral-Based Solid Oxide Fuel Cell with Heterogeneous Nanocomposite Derived from Hematite and Rare-Earth Minerals

Solid oxide fuel cells (SOFCs) have attracted much attention worldwide because of their potential for providing clean and reliable electric power. However, their commercialization is subject to the high operating temperatures and costs. To make SOFCs more competitive, here we report a novel and attractive nanocomposite hematite LaCePrOx (hematite LCP) synthesized from low-cost natural hematite and LaCePr-carbonate mineral as an electrolyte candidate. This heterogeneous composite exhibits a conductivity as high as 0.116 S cm(-1) at 600 degrees C with an activation energy of 0.50 eV at 400-600 degrees C. For the first time, a fuel cell using such a natural mineral-based composite demonstrates a maximum power density of 625 mW cm(-2) at 600 degrees C and notable power output of 386 mW cm(-2) at 450 degrees C. The extraordinary ionic conductivity and device performances are primarily attributed to the heterophasic interfacial conduction effect of the hematite-LCP composite. These superior properties, along with the merits of ultralow cost, abundant storage, and eco-friendliness, make the new composite a highly promising material for commercial SOFCs.