锂电池负极α-Fe2_O_3纳米粒子制备及电化学性能研究

Preparation of α- Fe_2O_3 Nanoparticles as Anode Materials and Its Electrochemical Characteristic Research for Lithium ion Battery

以高分子微球聚苯乙烯(PST)和聚甲基丙烯酸甲酯(PMMA)作为组装体,采用自组装方法在PST和PMMA微球表面自组装制备纳米α-Fe2O3电池负极材料,组装温度为PST(T=70℃)和PMMA(T=60℃)聚合温度。结果显示,采用PST作为组装体获得的α-Fe2O3纳米粒子颗粒更细,约70nm,粒径更均匀,分散性更好;而PMMA组装体获得的纳米粒径约80nm,分散性相对较差,主要原因是PMMA微球质地较软,易发生变形,而使α-Fe2O3纳米粒子吸附在PMMA表面不均匀,在热处理过程中受热不均导致α-Fe2O3纳米粒子尺寸不均,且有团聚趋势。XRD显示,两种组装体获得的均为纯相α-Fe2O3结构。电化学性能显示,采用PST作为组装体制备的纳米α-Fe2O3作为电池负极电化学性能明显优于PMMA组装体。

α-Fe2O3 nanopatticles as an anode material for lithium ion battery were prepared by self-assembly method on the surfaces of polystyrene （PST） and poly （methyl methacrylate） （PMMA） microspheres which were regarded as self-assembly bodies, the reaction temperature were the polymerization temperature, which was 70℃ for PST synthesis, 60℃ for PMMA synthesis. The results showed that α-Fe2O3 nanoparticles were finer when PST was used as self- assembly body. The nanoparticle size was about 70 nm with good uniformity and excellent dispersion. However, the size was 80nm without excellent dispersion when PMMA was used as self-assmebly body. The main reason was that PMMA microsphers were very soft, easy to be distorted which caused to α-Fe2O3 nanoparticles absorpt and were thermo-treated disuniformly on its surfaces, also there was reuniting phenomenon. XRD analyses showed that the samples prepared by the two self-assembly methods were pure α-Fe2O3 structures. Electrochemical analyses showed that the characteristic of α-Fe2O3 structures with PST as self-assembly body was exceller than that of α-Fe2O3 nanoparticles with PMMA as self-assembly body.