Defect-rich high-entropy spinel oxide catalyst for efficient vanadium redox flow battery
缺陷態高熵尖晶石氧化物觸媒應用於高效能釩氧化還原液流電池
📄 英文摘要
High entropy oxides (HEO) represent an innovative group of materials stabilized by incorporating configurational entropy. These materials are expected to display fascinating electrochemical properties. Herein, we successfully synthesized a defect-rich (CoCrFeMnNi)3O4 HEO catalyst with a single-phase spinel structure through a hydrothermal route pursued by calcination and, for the first time use it for vanadium redox flow battery (VRFB). Compared with monometallic oxide, Co3O4, and bimetallic oxide, (Fe,Co)3O4, the HEO catalyst reveals the utmost catalytic performance and reversibility towards the VO2+/VO2+ redox couple. Owing to the unique single-phase spinel structure and abundant oxygen vacancies, the VRFB flow cell using the HEO-modified heat-treated graphite felt (HEO-HGF) electrode achieves an outstanding energy efficiency of 79.23% and 70.58% at 160 and 240 mA/cm2, respectively, and shows good stability even for 500 cycles. This study provides new insight into other redox flow battery applications.
📄 中文摘要
高熵氧化物（HEO）是一類透過組態熵穩定的新型材料。這些材料預期將展現卓越的電化學性質。本研究中，我們透過水熱法結合退火處理，成功合成具有單相尖晶石結構的缺陷態 (CoCrFeMnNi)3O4 HEO 觸媒，並首次將其應用於釩氧化還原液流電池（VRFB）。相較於單金屬氧化物 Co3O4 與雙金屬氧化物 (Fe,Co)3O4，HEO 觸媒對 VO2+/VO2+ 氧化還原對展現最佳的催化性能與可逆性。由於其獨特的單相尖晶石結構與豐富的氧空位，使用 HEO 修飾熱處理石墨氈（HEO-HGF） electrode 的 VRFB 單電池在 160 mA/cm² 下達到 79.23% 的能量效率，在 240 mA/cm² 下達到 70.58%，並在 500 次循環後仍維持良好穩定性。本研究為其他氧化還原液流電池的開發提供了新的思路。
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