One-pot fabrication of high-entropy heterostructure cathode materials with excellent anti-poisoning properties in solid oxide fuel cells

Abstract

Degradation of cathode performance in solid oxide fuel cells (SOFCs), which is poisoned by atmospheric CO2 and volatilized Cr from steel connecting plates, is a key factor limiting the long-term stable operation. In this work, high entropy heterostructure La0.5Ba0.5Fe0.2Co0.2Ni0.2Cu0.2Mn0.2O3-δ@Ba2CuO3 (HE-LBF@BCO) is designed and prepared by the one-pot method to improve the anti-poisoning ability of the electrode against CO2 and Cr. Meanwhile, the Ba2CuO3 (BCO) heterostructure formed by self-assembly using atomic size effect improves the electrochemical performance. The peak power density with HE-LBF@BCO cathode reaches 789 mW cm−2 at 800 °C with the polarization impedance of 0.34 Ω cm2. To further extend the three-phase interface and enhance oxygen catalytic activity, for HE-LBF@BCO-Gd0.1Ce0.9O2-δ(GDC) composite cathode, the peak power density reaches 789 mW cm−2 and the polarization impedance decreases to 0.16 Ω cm2 at 800 °C, exhibiting a brilliant application potential of the high entropy cathode. More importantly, HE-LBF@BCO-GDC shows an outstanding stability both in CO2 and Cr-containing atmosphere. After testing in Cr-containing atmosphere at 0.8V, the current density of the single cell with HE-LBF@BCO-GDC cathode decreases from 250.86 to 208.64 mA cm−2 at 700 °C. The results confirm the design of high-entropy heterojunction electrode materials provides a new strategy to address the enhancement of SOFC performance.