Incorporating high acidity cations in Co-free BiFeO3-based air electrodes for enhancing their electrocatalytic activity and durability in reversible solid oxide cells†
{"title":"Incorporating high acidity cations in Co-free BiFeO3-based air electrodes for enhancing their electrocatalytic activity and durability in reversible solid oxide cells†","authors":"Shun Wang, Wen Jiang and Yifeng Zheng","doi":"10.1039/D4TA07490D","DOIUrl":null,"url":null,"abstract":"<p >Developing air electrodes with high catalytic activity and outstanding durability for the oxygen reduction and evolution reactions (ORR and OER) is crucial for the commercialization of reversible solid oxide cells (RSOCs). Co-free BiFeO<small><sub>3−<em>δ</em></sub></small>-based perovskite oxides are considered promising air electrode materials owing to the high polarizability of Bi<small><sup>3+</sup></small> and low oxygen-vacancy migration energy. In this work, we report the synthesis of Bi<small><sub>0.8</sub></small>Ca<small><sub>0.2</sub></small>Fe<small><sub>1−<em>x</em></sub></small>Ti<small><sub><em>x</em></sub></small>O<small><sub>3−<em>δ</em></sub></small> (BCFTi<small><sub><em>x</em></sub></small>, <em>x</em> = 0, 0.05, 0.1 and 0.15) perovskites as efficient air electrodes for RSOCs <em>via</em> A-/B-site co-doping engineering. Ca and Ti co-doping significantly improved the electrochemical performance and operational stability of BiFeO<small><sub>3</sub></small>-based air electrodes. Bi<small><sub>0.8</sub></small>Ca<small><sub>0.2</sub></small>Fe<small><sub>0.9</sub></small>Ti<small><sub>0.1</sub></small>O<small><sub>3−<em>δ</em></sub></small> (BCFTi<small><sub>0.1</sub></small>) exhibited the highest electrocatalytic activity with a polarization resistance of 0.064 Ω cm<small><sup>2</sup></small> in air at 700 °C in symmetrical cells, with a decrease of approximately 48% compared to BCF (0.123 Ω cm<small><sup>2</sup></small>). In addition, BCFTi<small><sub>0.1</sub></small> possessed excellent CO<small><sub>2</sub></small> tolerance and exhibited stable electroactivity in 3% CO<small><sub>2</sub></small>-air at 700 °C for 100 h. A fuel electrode-supported single cell with the BCFTi<small><sub>0.1</sub></small> air electrode demonstrated remarkable performance at 700 °C, achieving a power density of 1.03 W cm<small><sup>−2</sup></small> in fuel cell mode, which was about 88% higher than that of BCF (0.6 W cm<small><sup>−2</sup></small>). In electrolysis mode, a current density of 0.9 A cm<small><sup>−2</sup></small> was obtained at 700 °C and 1.3 V with 70% H<small><sub>2</sub></small>O–30% H<small><sub>2</sub></small>. The single cell with the BCFTi<small><sub>0.1</sub></small> air electrode demonstrated good cycling durability under humidified H<small><sub>2</sub></small> (10% H<small><sub>2</sub></small>O). The reduced activation energy for oxygen-ion migration and increased oxygen-vacancy concentration <em>via</em> Ca and Ti co-doping promoted surface oxygen exchange and bulk-transport kinetics, leading to enhanced electrocatalytic activity. At the same time, the high acidity of Ti<small><sup>4+</sup></small> and large average bonding energy enhanced the CO<small><sub>2</sub></small> tolerance of BCFTi<small><sub>0.1</sub></small>. This study provides a collaborative strategy for the regulation of A/B-site cations to design novel air electrodes with high activity and chemical stability for RSOCs.</p>","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":" 6","pages":" 4129-4141"},"PeriodicalIF":10.7000,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Materials Chemistry A","FirstCategoryId":"88","ListUrlMain":"https://pubs.rsc.org/en/content/articlelanding/2025/ta/d4ta07490d","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Developing air electrodes with high catalytic activity and outstanding durability for the oxygen reduction and evolution reactions (ORR and OER) is crucial for the commercialization of reversible solid oxide cells (RSOCs). Co-free BiFeO3−δ-based perovskite oxides are considered promising air electrode materials owing to the high polarizability of Bi3+ and low oxygen-vacancy migration energy. In this work, we report the synthesis of Bi0.8Ca0.2Fe1−xTixO3−δ (BCFTix, x = 0, 0.05, 0.1 and 0.15) perovskites as efficient air electrodes for RSOCs via A-/B-site co-doping engineering. Ca and Ti co-doping significantly improved the electrochemical performance and operational stability of BiFeO3-based air electrodes. Bi0.8Ca0.2Fe0.9Ti0.1O3−δ (BCFTi0.1) exhibited the highest electrocatalytic activity with a polarization resistance of 0.064 Ω cm2 in air at 700 °C in symmetrical cells, with a decrease of approximately 48% compared to BCF (0.123 Ω cm2). In addition, BCFTi0.1 possessed excellent CO2 tolerance and exhibited stable electroactivity in 3% CO2-air at 700 °C for 100 h. A fuel electrode-supported single cell with the BCFTi0.1 air electrode demonstrated remarkable performance at 700 °C, achieving a power density of 1.03 W cm−2 in fuel cell mode, which was about 88% higher than that of BCF (0.6 W cm−2). In electrolysis mode, a current density of 0.9 A cm−2 was obtained at 700 °C and 1.3 V with 70% H2O–30% H2. The single cell with the BCFTi0.1 air electrode demonstrated good cycling durability under humidified H2 (10% H2O). The reduced activation energy for oxygen-ion migration and increased oxygen-vacancy concentration via Ca and Ti co-doping promoted surface oxygen exchange and bulk-transport kinetics, leading to enhanced electrocatalytic activity. At the same time, the high acidity of Ti4+ and large average bonding energy enhanced the CO2 tolerance of BCFTi0.1. This study provides a collaborative strategy for the regulation of A/B-site cations to design novel air electrodes with high activity and chemical stability for RSOCs.
期刊介绍:
The Journal of Materials Chemistry A, B & C covers a wide range of high-quality studies in the field of materials chemistry, with each section focusing on specific applications of the materials studied. Journal of Materials Chemistry A emphasizes applications in energy and sustainability, including topics such as artificial photosynthesis, batteries, and fuel cells. Journal of Materials Chemistry B focuses on applications in biology and medicine, while Journal of Materials Chemistry C covers applications in optical, magnetic, and electronic devices. Example topic areas within the scope of Journal of Materials Chemistry A include catalysis, green/sustainable materials, sensors, and water treatment, among others.