Shoroshi Dey, Rajasekar Saravanan, Abimannan Sethurajaperumal, Rajaram Bal, Glenn C. Mather, Gadudhula Ganesh, Eswaraiah Varrla, Atharva Puranik, Kamil Nowicki, Madhumita Mukhopadhyay*, Amarnath R. Allu* and Jayanta Mukhopadhyay*,
{"title":"可逆固体氧化物电池双功能氧电催化剂：a位非化学计量对（La或Ba）0.6 - xsr0.4 co0.8 fe0.3 2o3−δ体系的影响","authors":"Shoroshi Dey, Rajasekar Saravanan, Abimannan Sethurajaperumal, Rajaram Bal, Glenn C. Mather, Gadudhula Ganesh, Eswaraiah Varrla, Atharva Puranik, Kamil Nowicki, Madhumita Mukhopadhyay*, Amarnath R. Allu* and Jayanta Mukhopadhyay*, ","doi":"10.1021/acsaem.5c0080310.1021/acsaem.5c00803","DOIUrl":null,"url":null,"abstract":"<p >Selective tailoring of stoichiometry in perovskite oxide generates excellent electrocatalytic activity toward redox reaction of oxygen [oxygen evolution reaction (OER) and oxygen reduction reaction (ORR)]. The redox reaction of oxygen is kinetically sluggish (spin relaxed reaction) and is the rate-limiting step for solid oxide cells (SOCs). We have reported that introducing non-stoichiometry at the A-site in A<sub>0.6–<i>x</i></sub>Sr<sub>0.4</sub>Co<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3−δ</sub> imparts a bifunctional electrocatalyst for OER and ORR with excellent performance in fuel cell (FC) and electrolyzer cell (EC) mode. Two compositions, Ba<sub>0.6</sub>Sr<sub>0.4</sub>Co<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3−δ</sub> (BSCF-6482) and La<sub>0.6</sub>Sr<sub>0.4</sub>Co<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3−δ</sub> (LSCF-6482), are designed by varying the non-stoichiometry from 0.6 to 0.52 for Ba and La, respectively. X-ray photoelectron spectroscopy (XP spectroscopy), iodometric estimation, and O<sub>2</sub>-temperature-programmed desorption (O<sub>2</sub>-TPD) reveal that Ba<sub>0.54</sub>Sr<sub>0.4</sub>Co<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3−δ</sub> (BS-54) promotes oxygen surface exchange (higher β-oxygen population) and La<sub>0.54</sub>Sr<sub>0.4</sub>Co<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3−δ</sub> (LS-54) accelerates α-oxygen desorption (charge-transfer reaction). A study of the distribution of relaxation time (DRT) using EIS (electrochemical impedance spectroscopy) on cell configuration LS-54 (or BS-54)/GDC-LS-54 (or BS-54)//GDC//Pt@800 °C reveals that LS-54 has minimum electrode polarization (comprising dual processes of charge transfer and oxygen surface exchange) at both +0.8 V (OER) and −0.8 V (ORR), which resonates at 10<sup>3</sup>–10<sup>4</sup> Hz. It is corroborated that α-oxygen is associated with the charge-transfer process and controls the ORR, whereas the OER is assisted by oxygen surface exchange, primarily linked with β-oxygen. Inclusion of non-stoichiometry at the A-site promotes oxygen-vacancy formation and stabilizes a lower valence state for the B-site cations. The rate-controlling steps for the OER and ORR thereby alter in LS-54 and BS-54 compared to LSCF/BSCF-6482. Electrochemical measurements show superior reversible solid oxide cell (SOC) performance of LS-54 having a current density (CD) of 1.27 A cm<sup>–2</sup> @1.5 V and 0.66 A cm<sup>–2</sup>@0.5 V for a cell with dimensions as large as 5 cm × 5 cm. A similar cell operated with a CD of 1.0 A cm<sup>2</sup> under standalone mode of operation in FC. This work proposes a novel strategy to demonstrate A-site non-stoichiometric La<sub>0.54</sub>Sr<sub>0.4</sub>Co<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3−δ</sub> to be a superior bifunctional electrocatalyst for both OER and ORR for SOCs.</p>","PeriodicalId":4,"journal":{"name":"ACS Applied Energy Materials","volume":"8 11","pages":"7433–7449 7433–7449"},"PeriodicalIF":5.5000,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Bi-Functional Oxygen Electrocatalysts for Reversible Solid Oxide Cells: The Influence of A-Site Non-stoichiometry on the System (La or Ba)0.6–xSr0.4Co0.8Fe0.2O3−δ\",\"authors\":\"Shoroshi Dey, Rajasekar Saravanan, Abimannan Sethurajaperumal, Rajaram Bal, Glenn C. Mather, Gadudhula Ganesh, Eswaraiah Varrla, Atharva Puranik, Kamil Nowicki, Madhumita Mukhopadhyay*, Amarnath R. Allu* and Jayanta Mukhopadhyay*, \",\"doi\":\"10.1021/acsaem.5c0080310.1021/acsaem.5c00803\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p >Selective tailoring of stoichiometry in perovskite oxide generates excellent electrocatalytic activity toward redox reaction of oxygen [oxygen evolution reaction (OER) and oxygen reduction reaction (ORR)]. The redox reaction of oxygen is kinetically sluggish (spin relaxed reaction) and is the rate-limiting step for solid oxide cells (SOCs). We have reported that introducing non-stoichiometry at the A-site in A<sub>0.6–<i>x</i></sub>Sr<sub>0.4</sub>Co<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3−δ</sub> imparts a bifunctional electrocatalyst for OER and ORR with excellent performance in fuel cell (FC) and electrolyzer cell (EC) mode. Two compositions, Ba<sub>0.6</sub>Sr<sub>0.4</sub>Co<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3−δ</sub> (BSCF-6482) and La<sub>0.6</sub>Sr<sub>0.4</sub>Co<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3−δ</sub> (LSCF-6482), are designed by varying the non-stoichiometry from 0.6 to 0.52 for Ba and La, respectively. X-ray photoelectron spectroscopy (XP spectroscopy), iodometric estimation, and O<sub>2</sub>-temperature-programmed desorption (O<sub>2</sub>-TPD) reveal that Ba<sub>0.54</sub>Sr<sub>0.4</sub>Co<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3−δ</sub> (BS-54) promotes oxygen surface exchange (higher β-oxygen population) and La<sub>0.54</sub>Sr<sub>0.4</sub>Co<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3−δ</sub> (LS-54) accelerates α-oxygen desorption (charge-transfer reaction). A study of the distribution of relaxation time (DRT) using EIS (electrochemical impedance spectroscopy) on cell configuration LS-54 (or BS-54)/GDC-LS-54 (or BS-54)//GDC//Pt@800 °C reveals that LS-54 has minimum electrode polarization (comprising dual processes of charge transfer and oxygen surface exchange) at both +0.8 V (OER) and −0.8 V (ORR), which resonates at 10<sup>3</sup>–10<sup>4</sup> Hz. It is corroborated that α-oxygen is associated with the charge-transfer process and controls the ORR, whereas the OER is assisted by oxygen surface exchange, primarily linked with β-oxygen. Inclusion of non-stoichiometry at the A-site promotes oxygen-vacancy formation and stabilizes a lower valence state for the B-site cations. The rate-controlling steps for the OER and ORR thereby alter in LS-54 and BS-54 compared to LSCF/BSCF-6482. Electrochemical measurements show superior reversible solid oxide cell (SOC) performance of LS-54 having a current density (CD) of 1.27 A cm<sup>–2</sup> @1.5 V and 0.66 A cm<sup>–2</sup>@0.5 V for a cell with dimensions as large as 5 cm × 5 cm. A similar cell operated with a CD of 1.0 A cm<sup>2</sup> under standalone mode of operation in FC. 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引用次数: 0
摘要
钙钛矿氧化物化学计量学的选择性裁剪对氧的氧化还原反应[析氧反应（OER）和氧还原反应（ORR）]产生了优异的电催化活性。氧的氧化还原反应在动力学上是缓慢的（自旋松弛反应），是固体氧化物电池（SOCs）的限速步骤。我们已经报道了在a0.6 - xsr0.4 co0.8 fe0.3 2o3−δ的a -位点引入非化学计量学，使OER和ORR双功能电催化剂在燃料电池（FC）和电解槽（EC）模式下具有优异的性能。Ba和La的非化学计量量分别为0.6 ~ 0.52，分别设计了Ba0.6Sr0.4Co0.8Fe0.2O3−δ (BSCF-6482)和La0.6Sr0.4Co0.8Fe0.2O3−δ (LSCF-6482)两种成分。x射线光电子能谱（XP）、碘量测定和o2程序升温解吸（O2-TPD）结果表明，Ba0.54Sr0.4Co0.8Fe0.2O3−δ (BS-54)促进氧表面交换（β-氧占比更高），La0.54Sr0.4Co0.8Fe0.2O3−δ (LS-54)加速α-氧解吸（电荷转移反应）。利用电化学阻抗谱（EIS）对LS-54（或BS-54）/GDC-LS-54（或BS-54）//GDC//Pt@800°C的弛豫时间（DRT）分布进行了研究，发现LS-54在+0.8 V （OER）和- 0.8 V （ORR）下具有最小的电极极化（包括电荷转移和氧表面交换的双重过程），共振频率为103-104 Hz。α-氧与电荷转移过程有关，并控制ORR，而OER则由氧表面交换辅助，主要与β-氧相关。在a位包含非化学计量促进氧空位的形成，并稳定了b位阳离子的低价态。因此，与LSCF/BSCF-6482相比，LS-54和BS-54的OER和ORR的速率控制步骤发生了变化。电化学测量表明，LS-54具有优异的可逆固体氧化物电池（SOC）性能，其电流密度（CD）为1.27 a cm - 2 @1.5 V和0.66 a cm - 2@0.5 V，电池尺寸为5 cm × 5 cm。类似的单元在FC中独立操作模式下以1.0 A cm2的CD操作。这项工作提出了一种新的策略来证明a位非化学计量La0.54Sr0.4Co0.8Fe0.2O3−δ是soc的OER和ORR的优越双功能电催化剂。
Bi-Functional Oxygen Electrocatalysts for Reversible Solid Oxide Cells: The Influence of A-Site Non-stoichiometry on the System (La or Ba)0.6–xSr0.4Co0.8Fe0.2O3−δ
Selective tailoring of stoichiometry in perovskite oxide generates excellent electrocatalytic activity toward redox reaction of oxygen [oxygen evolution reaction (OER) and oxygen reduction reaction (ORR)]. The redox reaction of oxygen is kinetically sluggish (spin relaxed reaction) and is the rate-limiting step for solid oxide cells (SOCs). We have reported that introducing non-stoichiometry at the A-site in A0.6–xSr0.4Co0.8Fe0.2O3−δ imparts a bifunctional electrocatalyst for OER and ORR with excellent performance in fuel cell (FC) and electrolyzer cell (EC) mode. Two compositions, Ba0.6Sr0.4Co0.8Fe0.2O3−δ (BSCF-6482) and La0.6Sr0.4Co0.8Fe0.2O3−δ (LSCF-6482), are designed by varying the non-stoichiometry from 0.6 to 0.52 for Ba and La, respectively. X-ray photoelectron spectroscopy (XP spectroscopy), iodometric estimation, and O2-temperature-programmed desorption (O2-TPD) reveal that Ba0.54Sr0.4Co0.8Fe0.2O3−δ (BS-54) promotes oxygen surface exchange (higher β-oxygen population) and La0.54Sr0.4Co0.8Fe0.2O3−δ (LS-54) accelerates α-oxygen desorption (charge-transfer reaction). A study of the distribution of relaxation time (DRT) using EIS (electrochemical impedance spectroscopy) on cell configuration LS-54 (or BS-54)/GDC-LS-54 (or BS-54)//GDC//Pt@800 °C reveals that LS-54 has minimum electrode polarization (comprising dual processes of charge transfer and oxygen surface exchange) at both +0.8 V (OER) and −0.8 V (ORR), which resonates at 103–104 Hz. It is corroborated that α-oxygen is associated with the charge-transfer process and controls the ORR, whereas the OER is assisted by oxygen surface exchange, primarily linked with β-oxygen. Inclusion of non-stoichiometry at the A-site promotes oxygen-vacancy formation and stabilizes a lower valence state for the B-site cations. The rate-controlling steps for the OER and ORR thereby alter in LS-54 and BS-54 compared to LSCF/BSCF-6482. Electrochemical measurements show superior reversible solid oxide cell (SOC) performance of LS-54 having a current density (CD) of 1.27 A cm–2 @1.5 V and 0.66 A cm–2@0.5 V for a cell with dimensions as large as 5 cm × 5 cm. A similar cell operated with a CD of 1.0 A cm2 under standalone mode of operation in FC. This work proposes a novel strategy to demonstrate A-site non-stoichiometric La0.54Sr0.4Co0.8Fe0.2O3−δ to be a superior bifunctional electrocatalyst for both OER and ORR for SOCs.
期刊介绍：
ACS Applied Energy Materials is an interdisciplinary journal publishing original research covering all aspects of materials, engineering, chemistry, physics and biology relevant to energy conversion and storage. The journal is devoted to reports of new and original experimental and theoretical research of an applied nature that integrate knowledge in the areas of materials, engineering, physics, bioscience, and chemistry into important energy applications.
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