Rationalization of Intercalation Potential and Redox Mechanism for A2Ti3O7 (A = Li, Na)
Rationalization of Intercalation Potential and Redox Mechanism for A2Ti3O7 (A = Li, Na)
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DOI：
10.1021/cm4032336
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发表时间：
2013-12
影响因子：
8.6
通讯作者：
G. Rousse;M. E. A. Dompablo;Premkumar Senguttuvan;A. Ponrouch;J. Tarascon;M. R. Palacín
中科院分区：
文献类型：
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作者：
G. Rousse;M. E. A. Dompablo;Premkumar Senguttuvan;A. Ponrouch;J. Tarascon;M. R. Palacín
Na 2 Ti 3 O 7由于其非常低的嵌入电压（0.3V vs Na+/Na 0）和高容量（200 mAh/g），最近被报道作为Na离子电池的负极材料是非常有前途的。本文研究了在Al_2 Ti_3 O_7（A = Li，Na）中，碱金属离子插层还原钛的氧化还原机理。即使还原相（A2+ xTi 3 O 7）的低稳定性排除了直接的研究，密度泛函理论（DFT）计算使我们能够提出还原相（A2+ xTi 3 O 7）的结构模型，这是进一步成功地面对现有的实验数据。碱金属原子在还原的A2+ xTi 3 O 7相中八面体配位，因此整个所得结构可以被认为是岩盐型。对于A = Li或A = Na，观察到离子插入的非常不同的电势清楚地证明，锂和钠系统之间的类比不能被认为是理所当然的。在这种情况下，这样的发现可以...
Na2Ti3O7 was recently reported to be highly promising as a negative electrode material for Na-ion batteries, thanks to its very low intercalation voltage (0.3 V vs Na+/Na0) and high capacity (200 mAh/g). The investigation of the redox mechanism in A2Ti3O7 (A = Li, Na) upon additional alkali ion intercalation concomitant to reduction of titanium is reported in this paper. Even if the low stability of the reduced phases (A2+xTi3O7) precluded a direct study, density functional theory (DFT) calculations allowed us to propose structural models for the reduced phases (A2+xTi3O7), which were further successfully confronted to the available experimental data. The alkali atoms are octahedrally coordinated in the reduced A2+xTi3O7 phase, so that the whole resulting structure can be considered rocksalt type. The very different potentials at which ion insertion is observed for A = Li or A = Na clearly prove that analogies between lithium and sodium systems cannot be taken for granted. In this case, such findings can ...