Electron‐Extraction Engineering Induced 1T’’‐1T’ Phase Transition of Re0.75V0.25Se2 for Ultrafast Sodium Ion Storage

• Published in: Advanced science Vol. 9; no. 36
• Main Authors: Fang, Yuqiang, Lv, Ximeng, Lv, Zhuoran, Wang, Yang, Zheng, Gengfeng, Huang, Fuqiang
• Format: Journal Article
• Language: English
• Published: Weinheim John Wiley & Sons, Inc 01.12.2022; John Wiley and Sons Inc; Wiley
• Subjects: 1T’ Re0.75V0.25Se2; Crystal structure; Energy; Engineering; phase transition; Phase transitions; Sodium; Spectrum analysis; ultrafast sodium‐ion storage
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202205680

Inducing new phases of transition metal dichalcogenides by controlling the d‐electron‐count has attracted much interest due to their novel structures and physicochemical properties. 1T’’ ReSe2 is a promising candidate for sodium storage, but the low electronic conductivity and limited active sites hinder its electrochemical capacity. Herein, new‐phase 1T’ Re0.75V0.25Se2 crystals (P2/m) with zig‐zag chains are successfully synthesized. The 1T’’‐1T’ phase transition results from the electronic reorganization of 5d orbitals via electron extraction after V‐atom doping. The electrical conductivity of 1T’ Re0.75V0.25Se2 is 2.7 × 105 times higher than that of 1T’’ ReSe2. Moreover, density functional theory (DFT) calculations reveal that 1T’ Re0.75V0.25Se2 has a larger interlayer spacing, lower bonding energy, and migration energy barrier for Na+ ions than 1T’’ ReSe2. As a result, 1T’ Re0.75V0.25Se2 electrode shows an excellent rate capability of 203 mAh g−1 at 50 C with no capacity fading over 5000 cycles for sodium storage, which is superior to most reported sodium‐ion anode materials. This 1T’ Re0.75V0.25Se2 provides a new platform for various applications such as electronics, catalysis, and energy storage. The phase transition of Re1‐xVxSe2 from 1T’’ to 1T’ phase can be achieved by decreasing the d‐electron count. The new‐phase 1T’ Re0.75V0.25Se2 has higher conductivity, larger interlayer distance, and lower migration energy barrier of Na+ ions, which results in an excellent rate capability of 203 mAh g−1 at 50 C with no capacity fading over 5000 cycles for sodium storage.