Lanthanum modified Fe3N/carbon foam as highly efficient electrode for zinc-air batteries

Abstract

Efficient electrocatalysts for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are of great importance for large-scale application of rechargeable zinc-air batteries. Iron-nitrogen-carbon materials are known for their excellent ORR catalytic activity, but it is their low OER performance that is responsible for poor charging operation causing slow market adoption of these energy storage devices. Herein, lanthanum (La) is applied to enhance OER electrocatalytic properties of iron-nitrogen-carbon materials used as zinc-air battery electrodes. According to X-ray diffractometry, the presence of La alters the electronic structure of surrounding N and Fe elements, resulting in more negative N and positive Fe ions to appear on the surface and form Fe3N active species. Electrochemical analysis demonstrated enhanced bi-functional electrocatalytic performance of La-modified Fe3N carbon foam (La-Fe0.1:1/NFC) which total overpotential was among the lowest of previously reported metal-nitrogen-carbon materials. La-Fe0.1:1/NFC exhibited high power density and charge-discharge cycling stability in a real zinc-air battery cell.