Unveiling the potential of oxygen-rich VNbMoTaWOx high-entropy catalyst for superior anode performance for sustainable vanadium redox flow batteries
揭示富氧 VNbMoTaWOx 高熵觸媒應用於永續釩氧化還原液流電池陽極的潛力
📄 英文摘要
High entropy alloy oxides (HEAOs) are a novel class of materials stabilized through configurational entropy, and they are anticipated to exhibit remarkable electrochemical properties. Here, we report the preparation of oxygen-rich amorphous VNbMoTaWOx HEAO thin films deposited on the surface of graphite felt (GF) electrode using a novel HiPIMS deposition technique intended for application in vanadium redox flow batteries (VRFBs). The modified GF electrode, featuring a 154 nm thick HEAO coating on the GF surface with an O/W ratio of 8.35, designated H#50, demonstrated superior electrocatalytic performance towards the VO⁺₂/VO₂⁺ redox couple, achieving energy efficiency values of 81.40 % at 100 mA cm⁻² and 71.40 % at 160 mA cm⁻². This represents a 7.70 % and 17.30 % improvement, respectively, over the uncoated GF electrode. The uniformly dispersed refractory metal, V, Nb, Mo, Ta, and W cations in the thin film, along with the optimal thickness, enable faster electron and ion transportation without obstructing the pores of GF. The diverse metal ions contribute to multiple oxidation states and abundant oxygen vacancies, which enhance the electroactive sites for the VO⁺₂/VO₂⁺ redox reaction. Additionally, this approach demonstrates remarkable cycling stability over 200 cycles.
📄 中文摘要
高熵合金氧化物（HEAOs）是一類透過組態熵穩定的新型材料，預期將展現卓越的電化學性質。本研究報告以新型 HiPIMS 鍍膜技術在石墨氈（GF） electrode 表面沉積富氧非晶 VNbMoTaWOx HEAO 薄膜，應用於釩氧化還原液流電池（VRFBs）。經改質的 GF electrode，名為 H#50，於 GF 表面鍍有 154 nm 厚的 HEAO 塗層，O/W 比為 8.35，對 VO⁺₂/VO₂⁺ 氧化還原對展現優異的電催化性能，在 100 mA cm⁻² 下達到 81.40% 的能量效率，在 160 mA cm⁻² 下達到 71.40%，分別較未鍍膜 GF electrode 提升 7.70% 與 17.30%。薄膜中均勻分散的 V、Nb、Mo、Ta、W 等難熔金屬離子，加上適當的厚度，使電子與離子傳輸更快，同時不堵塞 GF 的孔隙。多樣的金屬離子贡献多种氧化態與豐富的氧空位，增強了 VO⁺₂/VO₂⁺ 氧化還原反應的電活性位點。此外，此方法在 200 次循環中展現優異的循環穩定性。
🔬 五項核心重要發現
📊 關鍵圖表
