Oxygen reduction mechanisms in nanostructured La0.8Sr0.2MnO3 cathodes for Solid Oxide Fuel Cells

TL;DR

This study investigates how nanostructured La0.8Sr0.2MnO3 cathodes enhance oxygen reduction in SOFCs by improving oxide ion diffusion and gas phase oxygen transport, enabling lower operating temperatures and better performance.

Contribution

It reveals the mechanisms behind improved oxygen reduction in nanostructured LSM cathodes, emphasizing oxide ion diffusion and optimized gas diffusion as key factors.

Findings

Enhanced oxide ion diffusion through nanostructured cathodes

Reduced operating temperature for SOFCs using nanostructured LSM

Improved cathodic performance due to fast oxide ion transport

Abstract

In this work we outline the mechanisms contributing to the oxygen reduction reaction in nanostructured cathodes of La0.8Sr0.2MnO3 (LSM) for Solid Oxide Fuel Cells (SOFC). These cathodes, developed from LSM nanostructured tubes, can be used at lower temperatures compared to microstructured ones, and this is a crucial fact to avoid the degradation of the fuel cell components. This reduction of the operating temperatures stems mainly from two factors: i) the appearance of significant oxide ion diffusion through the cathode material in which the nanostructure plays a key role and ii) an optimized gas phase diffusion of oxygen through the porous structure of the cathode, which becomes negligible. A detailed analysis of our Electrochemical Impedance Spectroscopy supported by first principles calculations point towards an improved overall cathodic performance driven by a fast transport of oxide ions through the cathode surface.