Regulating Fe-O bond in Ti3C2Tx MXene anode for high-capacity Li-ion batteries
Regulating Fe-O bond in Ti3C2Tx MXene anode for high-capacity Li-ion batteries
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调节高容量锂离子电池 Ti3C3TX MXene 阳极中的 Fe-O 键
DOI：
10.1016/j.cej.2021.130018
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发表时间：
2021
影响因子：
15.1
通讯作者：
Wang Xi
中科院分区：
文献类型：
--
作者：
Zhao Nana;Yang Yijun;Yi Ding;Xiao Yubao;Wang Ke;Cui Weibin;Wang Xi
化学键合被认为是提高锂离子电池用MXene电化学性能的有效改性策略。然而，深入的机制，特别是集中在化学键的调控，很少有人探讨。在此，我们设计了一个原子分散的Fe在Ti 3C 2 TxMXene（Fe-Ti 3C 2 Tx）的掺杂路线和高容量LIB的潜在机制进行了全面的研究。密度泛函理论（DFT）计算结果表明，Fe-O键上的电子转移可以诱导不饱和O配位，从而提高了Fe-Ti 3C 2 Tx纳米片在充放电过程中对Li离子的吸附。X射线光电子能谱（XPS）和X射线吸收谱（XAS）的实验结果证实了Fe原子成功地引入到Ti 3C 2 TxMXene的本征结构中，并证实了Fe-O键的电子转移。此外，Fe-Ti 3C 2 Tx电极表现出极大增强的电化学性能（564.9 mAh g− 1 at 50 mA g− 1 under −10 °C），超过了原始Ti 3C 2 Tx（77 mAh g−1）。Fe-Ti 3C 2 Tx的500次循环稳定性（-10 °C下200 mA g − 1时为418.8 mAh g− 1）。这一工作有望为开发具有高储能容量的全新MXene基电极材料提供指导。
Chemical bonding has been regarded as an effective modification strategy to enhance the electrochemical performance of MXenes for Li-ion batteries (LIBs). However, the in-depth mechanism, especially concentrating on the regulation of chemical bond, is rarely explored. Herein, we design an atomically dispersed Fe in Ti3C2TxMXene (Fe-Ti3C2Tx) by a doping route and the underlying mechanism of high-capacity LIBs is comprehensively investigated. Density functional theory (DFT) calculations reveal that unsaturated O coordination can be induced by electron transfer on Fe–O bond, which enables improved Li-ion adsorption on the surface of Fe-Ti3C2Txnanosheet during charge/discharge process. The experimental observations from X-ray photoelectron spectroscopy (XPS) confirm the successful introduction of Fe atoms into intrinsic structure of Ti3C2TxMXene, and the X-ray absorption spectroscopy (XAS) data verify the electron transfer of Fe–O bond. Moreover, Fe-Ti3C2Txelectrode exhibits greatly enhanced electrochemical performance (564.9 mAh g−1at 50 mA g−1under −10 °C), surpassing that of pristine Ti3C2Tx(77 mAh g−1). The cycling stability of Fe-Ti3C2Txover 500 cycles (418.8 mAh g−1at 200 mA g−1under −10 °C). This work is expected to provide a guideline to develop brand-new MXene-based electrode materials with high-capacity for energy storage.