纳米针状Li_(2)MnSiO_(4)正极材料的合成及电化学性能研究

Synthesis of nanoneedle-like Li_(2)MnSiO_(4)cathode material for lithium-ion batteries and study on its electrochemical properties

基于Li_(2)MnSiO_(4)结构锂离子迁移的各向异性特征,提出了一种调控材料晶面生长取向的水热合成方法,以提高材料的电化学性能。利用X射线衍射(XRD)､扫描电镜(SEM)､透射电镜(TEM)以及X射线光电子能谱(XPS)等对产物进行表征。结果表明,产物呈纳米针状(长为200 nm,宽度为30 nm),具有特定晶面暴露的特征。其特殊的纳米结构展现出良好的电化学性能,在0.1 C倍率下,放电比容量达到217.3 mAh/g。

Based on the anisotropic characteristics of Li+ions migration in Li_(2)MnSiO_(4)structure,a hydrothermal method is proposed to synthesize the nano-grade needle-like Li_(2)MnSiO_(4)crystals,which can regulate the preferential growth of the crystal plane and improve the electrochemical performance of Li_(2)MnSiO_(4)cathode material.The crystal structure and morphology of the products are characterized by using X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).It is shown that the product displays a nanoneedle-like morphology(200 nm in length and 30 nm in width)with a specific face-exposed structure.Benefitting from the particular nanoneedle morphology,Li_(2)MnSiO_(4)cathode materials exhibit good electrochemical performance,delivering a discharge capacity of 217.3 mAh·g^(-1)at 0.1 C.