A comprehensive and comparative exploration research performed, aiming to elucidate the fundamental mechanisms of rare-earth (RE) metal-ion doping into Li₄Ti₅O₁₂ (LTO), reveals the enhanced electrochemical performance of the nanocrystalline RE-LTO electrodes in high-power Li-ion batteries. Pristi ne Li₄Ti₅O₁₂ (LTO) and rare-earth metal-doped Li_4–x/3Ti_5–2x/3Ln_xO₁₂ (RE-LTO with RE = Dy, Ce, Nd, Sm, and Eu; x ≈ 0.1) nanocrystalline anode materials were synthesized using a simple mechanochemical method and subsequent calcination at 850 °C. The X-ray diffraction (XRD) patterns of pristine and RE-LTO samples exhibit predominant (111) orientation along with other characteristic peaks corresponding to cubic spinel lattice. No evidence of RE-doping-induced changes was seen in the crystal structure and phase. The average crystallite size for pristine and RE-LTO samples varies in the range of 50–40 nm, confirming the formation of nanoscale crystalline materials and revealing the good efficiency of the ball-milling-assisted process adopted to synthesize nanoscale particles. Raman spectroscopic analyses of the chemical bonding indicate and further validate the phase structural quality in addition to corroborating with XRD data for the cubic spinel structure formation. Transmission electron microscopy (TEM) reveals that both pristine and RE-LTO particles have a similar cubic shape, but RE-LTO particles are better interconnected, which provide a high specific surface area for enhanced Li⁺-ion storage. The detailed electrochemical characterization confirms that the RE-LTO electrodes constitute promising anode materials for high-power Li-ion batteries. The RE-LTO electrodes deliver better discharge capacities (in the range of 172–198 mAh g^–1 at 1C rate) than virgin LTO (168 mAh g^–1). Among them, Eu-LTO provides the best discharge capacity of 198 mAh g^–1 at a 1C rate. When cycled at a high current rate of 50C, all RE-LTO electrodes show nearly 70% of their initial discharge capacities, resulting in higher rate capability than virgin LTO (63%). The results discussed in this work unfold the fundamental mechanisms of RE doping into LTO and demonstrate the enhanced electrochemical performance derived via chemical composition tailoring in RE-LTO compounds for application in high-power Li-ion batteries.

中文翻译：

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稀土金属离子掺杂纳米晶 Li4Ti5O12 电极在高功率锂离子电池中的增强电化学性能

一项全面的比较探索研究旨在阐明稀土 (RE) 金属离子掺杂到 Li ₄ Ti ₅ O ₁₂ (LTO) 中的基本机制，揭示了纳米晶 RE-LTO 电极在高温下增强的电化学性能-动力锂离子电池。原始 Li ₄ Ti ₅ O ₁₂ (LTO) 和稀土金属掺杂 Li _{4– x /3} Ti _{5–2 x /3} Ln _x O ₁₂ (RE-LTO with RE = Dy, Ce, Nd, Sm,和欧盟; x≈ 0.1) 使用简单的机械化学方法合成纳米晶阳极材料，然后在 850 °C 下进行煅烧。原始样品和 RE-LTO 样品的 X 射线衍射 (XRD) 图案表现出主要 (111) 取向以及对应于立方尖晶石晶格的其他特征峰。在晶体结构和相中没有看到 RE 掺杂引起变化的证据。原始和 RE-LTO 样品的平均微晶尺寸在 50-40 nm 范围内变化，证实了纳米级晶体材料的形成，并揭示了用于合成纳米级颗粒的球磨辅助工艺的良好效率。化学键合的拉曼光谱分析表明并进一步验证了相结构质量，此外还证实了立方尖晶石结构形成的 XRD 数据。透射电子显微镜 (TEM) 显示原始和 RE-LTO 颗粒都具有相似的立方体形状，但 RE-LTO 颗粒之间的相互连接更好，这为增强的 Li 提供了高比表面积^{+ -}离子存储。详细的电化学表征证实，RE-LTO 电极构成了用于高功率锂离子电池的有前途的阳极材料。与原始 LTO (168 mAh g ^–1 ) 相比，RE-LTO 电极具有更好的放电容量（在 1C 倍率下在 172–198 mAh g –1 范围内^）。其中，Eu-LTO在 1C 倍率下提供 198 mAh g ^–1的最佳放电容量。当以 50C 的高电流率循环时，所有 RE-LTO 电极显示出其初始放电容量的近 70%，从而导致比原始 LTO (63%) 更高的倍率能力。这项工作中讨论的结果揭示了 RE 掺杂到 LTO 中的基本机制，并证明了通过RE-LTO 化合物的化学成分定制，用于高功率锂离子电池。