Surface Amorphization of Vanadium Dioxide (B) for K-Ion Battery
Surface Amorphization of Vanadium Dioxide (B) for K-Ion Battery
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钾离子电池用二氧化钒（B）的表面非晶化
DOI：
10.1002/aenm.202000717
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发表时间：
2020-04-29
影响因子：
27.8
通讯作者：
Lu, Jun
中科院分区：
文献类型：
--
作者：
Li, Youpeng;Zhang, Qiaobao;Lu, Jun
鉴于成本低、电解质中离子传输速度快以及工作电压高等优点，钾离子电池（PIB）是锂离子电池的有前途的替代品。然而，开发能够可逆容纳大钾离子的合适电极材料是一个巨大的挑战。在这里，以密度泛函理论（DFT）计算为指导，证明了通过VO2（B）纳米棒（SA-VO2）表面非晶化的界面工程策略，导致形成结晶核/非晶壳异质结构，在大容量、出色的倍率性能和用作PIB阳极时的长循环稳定性方面实现了优异的K+存储性能。 DFT 计算表明，SA-VO2 中形成的晶体/非晶异质界面可以显着降低表面能，缩小带隙，并降低 VO2 的 K+ 扩散势垒 (B)。这些条件可以增强 K+ 存储容量和快速 K+/电子转移，从而实现大容量和出色的倍率性能。利用原位 X 射线衍射和原位透射电子显微镜，并辅以异位显微镜和光谱技术，揭示了 SA-VO2 优异的循环稳定性源于优异的相可逆性、可忽略的应变响应和 SA-VO2 在（脱）钾后的稳健机械行为。
Given the merits of low cost, fast ionic transport in electrolyte, and high operating voltage, potassium ion batteries (PIBs) are promising alternatives to lithium-ion batteries. However, developing suitable electrode materials that can reversibly accommodate large potassium ions is a great challenge. Here, guided by density functional theory (DFT) calculations, it is demonstrated that the strategy of interfacial engineering via surface amorphization of VO2 (B) nanorods (SA-VO2), which results in the formation of a crystalline core/amorphous shell heterostructure, enables superior K+ storage performance in terms of large capacity, outstanding rate capability, and long cycle stability working as an anode for PIBs. DFT calculations reveal that the created crystalline/amorphous heterointerface in SA-VO2 can substantially lower the surface energy, narrow the band gap, and reduce the K+ diffusion barrier of VO2 (B). These conditions enable enhanced K+ storage capacity and rapid K+/electron transfer, which result in large capacity and outstanding rate capability. Using in situ X-ray diffraction and in situ transmission electron microscopy complemented by ex situ microscopic and spectroscopic techniques, it is unveiled that the superior cycling stability originates from the excellent phase reversibility with negligible strain response and robust mechanical behavior of SA-VO2 upon (de)potassiation.