Open-Structured Oxyfluorinated Titanium Phosphate Nanosheets Synthesized with the Assistance of an Ionic Liquid and Their Use as an Anode in Lithium-Ion Batteries

作者：Ruiqin Gao, Mengfei Yu, Hui Xu, Lichun Li, Meng Deng, Yuxue Wu, Zhengfei Chen · 发表于：Energy & Fuels · 年份：2021 · DOI：10.1021/acs.energyfuels.1c02635 · 被引用次数：36 · 研究领域：Advancements in Battery Materials、Supercapacitor Materials and Fabrication、Advanced Battery Materials and Technologies

Two-dimensional Ti 2 (PO 4 ) 2 F nanosheets were synthesized with an ionic liquid (IL) containing PF 6 ([Bmim]PF 6 ) via a hydrothermal method. In comparison, only anatase titanium dioxide (TiO 2 ) nanoparticles were obtained when changing the type of anion ([Bmim]Br or [Bmim]BF 4 ) under the same conditions, suggesting that the anion type could greatly affect the crystalline phase, particle size, specific surface, and morphology of the final products; two-dimensional nanosheets were obtained in [Bmim]PF 6, whereas nanocrystals with a relatively large surface were formed in the latter two ILs, as revealed by X-ray diffraction, nitrogen gas sorption, scanning electron microscopy, and transmission electron microscopy measurements. 1 H and 19 F nuclear magnetic resonance examinations of the fresh and recycled ILs suggest that the IL with the PF 6 anion experienced complete hydrolysis, which could be the key factor for the formation of such unique Ti 2 (PO 4 ) 2 F nanosheets. The electrochemical performances of such Ti 2 (PO 4 ) 2 F nanosheets were evaluated as anode materials in lithium-ion batteries (LIBs) in comparison to TiO 2 nanomaterials. The rate capability and cycling performance of the Ti 2 (PO 4 ) 2 F electrode outperformed the other two electrodes studied, as illustrated by cyclic voltammetry curves, charge/discharge behavior, and long cycling test, which is mainly due its unique layered structure and low surface area, which resulted in low volume change. The Ti 2 (PO...