Solid oxidefuel cells with both high voltage and power output by utilizing beneficial interfacial reaction

Abstract

An intriguing cell concept by applying proton-conducting oxide as the ionic conducting phase in the anode and taking advantage of beneficial interfacial reaction between anode and electrolyte is proposed to successfully achieve both high open circuit voltage (OCV) and power output for SOFCs with thin-film samarium doped ceria (SDC) electrolyte at temperatures higher than 600 °C. The fuel cells were fabricated by conventional route without introducing an additional processing step. A very thin and dense interfacial layer (2–3 μm) with compositional gradient was created by in situ reaction between anode and electrolyte although the anode substrate had high surface roughness (>5 μm), which is, however, beneficial for increasing triple phase boundaries where electrode reactions happen. A fuel cell with Ni–BaZr_0.4Ce_0.4Y_0.2O₃ anode, thin-film SDC electrolyte and Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3–δ (BSCF) cathode has an OCV as high as 1.022 V and delivered a power density of 462 mW cm⁻² at 0.7 V at 600 °C. It greatly promises an intriguing fuel cell concept for efficient power generation.