单斜层状LiMnO_2的球磨-离子交换法合成及其电化学性能研究

Synthesis and Electrochemical Properties of Monoclinic LayeredLiMnO_2 via Ball-milling and Ion Exchange Reaction

通过球磨促进固相反应法合成出了具有单斜层状结构的前驱物NaMnO2,随后通过离子交换得到了单斜层状LiMnO2。XRD测试结果显示产物为单相。扫描电镜(SEM)和透射电镜(TEM)观测结果显示LiMnO2的粒子尺寸为300￣500nm,HRTEM分析显示干扰条纹的间距为0.485nm,基本对应于m-LiMnO2的(001)晶面间距。红外吸收光谱(IR)和X射线光电子能谱(XPS)被用来测量m-LiMnO2中Mn-O键的伸缩和弯曲振动吸收和Mn元素的价态。合成的m-LiMnO2在电化学充放电循环初期表现了较好的电化学性能,但其循环寿命仍需要进一步改善。

The precursor compound of NaMnO2 With a layered monoclinic structure was synthesized by a method of ball-milling-promoted solid-state reaction. And then pure LiMnO2 with fine structure was obtained via a subsequent ion exchange reaction. The LiMnO2 material was detected as a single phase with a layered monoclinic structure by X-ray diffraction (XRD). The particle size of the m-LiMnO2 material was about 300 similar to 500 nm by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The well-resolved interference fringe spacing is about 0.485 nm from HRTEM, which is consistent with the (001) plane in monoclinic LiMnO2 phase. Infrared (IR) and X-ray Photoelectron Spectra (XPS) were used to measure the stretching and bending vibrations of Mn-O bond and valence state of Mn element in m-LiMnO2 material. The obtained m-LiMnO2 was shown to have a good electrochemical performance as a cathode material for lithium ion batteries.