聚阴离子掺杂LiMnO_(2-y)X_y(X=BF_4~-,SiO_3~(2-),MoO_4~(2-),PO_4~(3-),BO_3~(3-))材料的合成及其电化学性能

采用水热法合成了聚阴离子掺杂LiMnO2-yXy(X=BF4-,SiO32-,MoO42-,PO43-,BO33-,y=0.01、0.03、0.05)锂离子电池正极材料。通过X射线粉末衍射(XRD)、X光电子能谱(XPS)、扫描电镜(SEM)和恒电流充放实验,研究了不同掺杂离子和掺杂量对产物结构和电化学性能的影响。结果表明,少量聚阴离子的掺杂未改变正交LiMnO2的晶体类型,但增大了材料晶胞体积,改善了材料的电化学循环性能。电化学交流阻抗(EIS)测试结果表明,聚阴离子掺杂增大了材料电荷转移阻抗,但明显提高了材料中Li+的扩散能力。

Synthesis and Electrochemical Properties of Polyanion Doped LiMnO2-yXy(X=BF4-, SiO32-, MoO42-, PO43-, BO33-)

Hydrothermal methods were used to prepare the polyanion-doping LiMnO_2-yX_y(X=BF₄^-, SiO₃^2-, MoO₄^2-, PO₄^3-, BO₃^3-) as cathode materials for lithium-ion batteries. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), scanning electron microscope (SEM) and their electrochemical performances were investigated including cycling behavior (CV) and constant current charge-discharge experiment. The results indicate that the low concent ration polyanion dopant does not affect the crystal type of orthorhombic LiMnO₂ but considerable improves its electrochemical performances. Electrochemical impedance spectroscopy (EIS) analysis shows that the charge-tranfer resitance and the Warburg impendance decrease obviously as compared to that the undoped LiMnO₂ samples, however, The large polyanion doping can enhances fast mobility of Li⁺ ions.