High-Rate Lithium Cycling and Structure Evolution in Mo4O11
High-Rate Lithium Cycling and Structure Evolution in Mo4O11
复制标题
Mo4O11 中的高速率锂循环和结构演化
DOI：
10.1021/acs.chemmater.2c00420
复制
发表时间：
2022
影响因子：
8.6
通讯作者：
R. Seshadri
中科院分区：
文献类型：
--
作者：
Rebecca C. Vincent;Yunkai Luo;Jessica L. Andrews;Arava Zohar;Yucheng Zhou;Qizhang Yan;Eve M. Mozur;M. Preefer;J. Weker;A. Cheetham;Jian Luo;L. Pilon;B. Melot;B. Dunn;R. Seshadri
剪切相早期过渡金属氧化物，主要是Nb，由边缘和角落共享的金属−氧八面体组成，近年来作为锂离子电池的快速充电、低压电极重新流行起来。总的来说，钼氧化物作为快速充电电极的研究较少。这里我们研究了一种还原的钼氧化物Mo4O11，它的结构只包含角连接的MoO4四面体和MoO6八面体。结果表明，以微米级的Mo4O11为活性物质制成的电极可以作为锂离子对锂离子的高速电极，在5℃的高倍率下，其容量稳定在200mAhg−1以上。利用X-射线衍射谱、熵势测量和非原位拉曼光谱对电荷存储的性质进行了研究。fi第一次锂化后晶体结构发生显著变化，随后的循环是完全可逆的，容量衰减很小。正是这种新形成的、可能更具层次感的结构展示了高速循环和小电压极化。提出了新结构的空间群和单胞结构。这一fiNDIND将候选高倍率电极材料的范围扩大到预期的含Nb剪切相氧化物材料之外。
: Shear-phase early transition metal oxides, mostly of Nb, and comprising edge- and corner-shared metal − oxygen octahedra have seen a resurgence in recent years as fast-charging, low-voltage electrodes for Li + -ion batteries. Mo oxides, broadly, have been less well studied as fast-charging electrodes. Here we examine a reduced Mo oxide, Mo 4 O 11 , that has a structure comprising only corner-connected MoO 4 tetrahedra and MoO 6 octahedra. We show that an electrode formed using micrometer-sized particles of Mo 4 O 11 as the active material can function as a high-rate Li + -ion electrode against Li metal, with a stable capacity of over 200 mAh g − 1 at the high rate of 5 C . Operando X-ray di ff raction (XRD), entropic potential measurements, and ex situ Raman spectroscopy are employed to understand the nature of the charge storage. The crystal structure dramatically changes upon the fi rst lithiation, and subsequent cycling is completely reversible with low capacity fade. It is the newly formed and potentially more layered structure that demonstrates high-rate cycling and small voltage polarization. A space group and unit cell for the new structure is proposed. This fi nding expands the scope of candidate high-rate electrode materials to those beyond the expected Nb-containing shear-phase oxide materials.