| Sn4P3 has a layered crystal structure and its special structure makes it having broad industrial applications, especially in the field of anode materials and catalysts. It has recently become a hot spot owing to unique physical and chemical properties and is considered as a promising anode material. However, the development of a facile, low-temperature synthesis of such novel shape Sn4P3 nanocrystals and improving performances remains a great challenge. So, it is very meaningful to investigate the synthesis and characterization of tin phosphide and its modified materials.In this paper, Sn4P3 and its modified materials were successfully farbricated. Their formation process and reaction mechanism was also investigated. Moreover, their performances were further reported. The main contents are summarized as follows:1. Synthesis, Characterization and performances of hollow spherical Sn4P3 microstructures.Sn4P3 hollow spherical microstructures were successfully synthesized by a facile Solvothermal approach, using stannous chloride and white phosphorus as a main raw material, ethylenediamine tetraacetic acid (EDTA) as complexing agent. The morphology and structure of the as-obtained Sn4P3 hollow microspheres were characterized by X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and field-emission scanning electron microscopy (FE-SEM). The results indicated that the amount of EDTA and reaction time are important to the morphology and size of the Sn4P3 of hollow spherical microstructures. Then based on some condition experiment, the possible growth mechanism and reaction process of the as-prepared hollow microspheres was proposed. The research displays that the as-prepared Sn4P3 catalysts could absorb some typical organic dyes such as Methylene Blue, Safranine T and Methyl Orange, especially the adsorption ratio for some could reach to 99%. Meanwhile, as anode materials for lithium ion batteries, the initial discharge capacity of the as-prepared Sn4P3 hollow microspheres exceed 1478 mAh/g at 100 mA/g and it still keeps at 261 mAh/g after 20 cycles. Even the current density is increased to 500 mA/g, the second discharge capacity still can attain to 689 mAh/g.2. Synthesis, Characterization and electrochemical performances of Sn4P3 nanoparticles.Sn4P3 nanoparticles were successfully synthesized by a facile solvothermal approach, using N, N-dimethylformamide (DMF) and absolute ethyl alcohol (Ethanol) as solvents with the adding of NaBH4. The morphology and structure of the as-obtained Sn4P3 nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and field-emission scanning electron microscopy (FE-SEM). The materials characterization showed that the Sn4P3 nanoparticles can be indexed as the pure hexagonal Sn4P3 phase, the main diffraction peaks are intensive and narrow, which manifest good crystallinity of the as-synthesized Sn4P3 nanoparticles. The as-prepared Sn4P3 nanoparticles have an average size of about 15 nm. It is found that the solvent ratio is an important factor in controlling the size of the as-prepared Sn4P3 sample. It was found that the optimum preparation conditions were that the VDMF:VEthanol= 1:3, the reaction temperature was 180 ℃ and the reaction time was 10 h. Then, the long cycle stability and rate performance of the as-obtained Sn4P3 nanoparticles have been tested as an anode material for lithium ion batteries for the first time. Electrochemical measurements show that the Sn4P3 nanoparticles with a smallest size give the best cycling and rate performances. They could still maintain 442 mAh/g after 320 cycles at the current density of 100 mA/g within voltage limit of 0.01-3.0 V. Even after 200 and 100 cycles at a current density of 200 and 500 mA/g, respectively, the specific capacity still could be remained at 315 and 270 mAh/g, respectively. Finally, the as-prepared Sn4P3 nanoparticles have also been tested as an anode material for Na-ion batteries, this Sn4P3 anode can deliver a reversible capacity of 305 mAh/g after 10 cycles at the current density of 50 mA/g. These results demonstrate the potential application of the Sn4P3 electrode in rechargeable batteries.3. Synthesis, Characterization and electrochemical performances of Mn-doped Sn4P3 nanoparticles.The various molar concentrations of manganese (Mn)-doped Sn4P3 nanoparticles were synthesized via a novel and facile ultrasonic assisted hydrothermal method and characterized in detail by various analytical techniques. The X-ray diffraction (XRD), transmission electron microscopy (TEM) and field-emission scanning electron microscopy (FE-SEM) results showed that Mn ion was successfully substituted on the Sn4P3 layered structure without any structure changes. The long cycle stability of the as-prepared Mn-doped Sn4P3 nanoparticles have been tested as an anode material for lithium ion batteries at the different current density. By detailed experimental results exhibited that the Mn dopant content crucially determines the electrochemical performances of Sn4P3 nanoparticles. Electrochemical measurements show that the Sn4P3 nanoparticles with 0.10 mol% molar concentration of Mn dopant give the best cycling performances. They deliver a discharge capacity of 488 mAh/g after 150 cycles at the current density of 100 mA/g. Even after 140 cycles at a current density of 200 mA/g, the specific capacity still could be remained at 423 mAh/g. Further increasing the current density to 1000 mA/g, it could still maintain 318 mAh/g after 90 cycles. It is confirmed that Mn substitution in the Sn-Mn-P structure is an important pole to improve the structure stability and electrochemical properties. The results showed that Mn-doped Sn4P3 modified materials exhibited more excellent electrochemical performance. |
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