A niobium oxide with a shear structure and planar defects for high-power lithium ion batteries
A niobium oxide with a shear structure and planar defects for high-power lithium ion batteries
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一种具有剪切结构和平面缺陷的铌氧化物，用于高功率锂离子电池
DOI：
10.1039/d1ee02664j
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发表时间：
2022
影响因子：
32.5
通讯作者：
Zhang, Weilin
中科院分区：
文献类型：
--
作者：
Li, Tongtong;Nam, Gyutae;Liu, Kuanting;Wang, Jeng-Han;Zhao, Bote;Ding, Yong;Soule, Luke;Avdeev, Maxim;Luo, Zheyu;Zhang, Weilin
高倍率性能负极材料的开发是高功率锂电池的关键。T-Nb_2 O_5具有良好的准电容性能和快速储锂能力。然而，在较高温度下制备的Nb 2 O 5的其他多晶型物具有实现比T-Nb 2 O 5更高的比容量和振实密度的潜力，提供更高的体积功率和能量密度。在这里，具有丰富的Wadsley平面缺陷的微米级H-Nb 2 O 5（表示为d-H-Nb 2 O 5）被设计用于快速锂存储。H-Nb 2 O 5的[NbO 6]八面体块的局部重排的性能优于T-Nb 2 O 5的比容量，倍率性能，和稳定性。通过操作X-射线吸收光谱，观察到有缺陷的H-Nb 2 O 5锂化后铌离子的化合价的变化范围很宽。操作扩展的X射线吸收精细结构和非原位拉曼光谱分析揭示了一个大的和可逆的扭曲的结构在两相区。计算和非原位X射线衍射分析表明，剪切结构沿着主要的锂扩散路径扩展，并在垂直于剪切面的方向收缩。平面缺陷通过块体的垂直排列来缓解应变，最大限度地减少体积变化并增强结构稳定性。此外，强的Li吸附在平面缺陷上增大了嵌入容量。与纳米结构工程不同的是，我们对体相中的平面缺陷进行修饰的策略可以有效地改善本征性质。这项工作中的发现为通过缺陷工程设计微米尺寸的快速锂离子存储材料提供了新的见解，该策略适用于其他能源相关应用的材料发现。
The development of anode materials with high-rate capability is critical to high-power lithium batteries. T-Nb2O5 has been widely reported to exhibit pseudocapacitive behavior and fast lithium storage capability. However, the other polymorphs of Nb2O5 prepared at higher temperatures have the potential to achieve even higher specific capacity and tap density than T-Nb2O5, offering higher volumetric power and energy density. Here, micrometer-sized H-Nb2O5 with rich Wadsley planar defects (denoted as d-H-Nb2O5) is designed for fast lithium storage. The performance of H-Nb2O5 with local rearrangements of [NbO6] octahedra blocks surpasses that of T-Nb2O5 in terms of specific capacity, rate capability, and stability. A wide range variation in the valence of niobium ions upon lithiation was observed for defective H-Nb2O5via operando X-ray absorption spectroscopy. Operando extended X-ray absorption fine structure and ex situ Raman spectroscopy analyses reveal a large and reversible distortion of the structure in the two-phase region. Computation and ex situ X-ray diffraction analysis reveal that the shear structure expands along major lithium diffusion pathways and contracts in the direction perpendicular to the shear plane. Planar defects relieve strain through perpendicular arrangements of blocks, minimizing volume change and enhancing structural stability. In addition, strong Li adsorption on planar defects enlarges intercalation capacity. Different from nanostructure engineering, our strategy to modify the planar defects in the bulk phase can effectively improve the intrinsic properties. The findings in this work offer new insights into the design of fast Li-ion storage materials in micrometer sizes through defect engineering, and the strategy is applicable to the material discovery for other energy-related applications.