采用液相法合成了Li_2MnSiO_4/C复合正极材料,并研究了不同焙烧温度对材料的结构、形貌和电化学性能的影响.利用热重(TG)分析了材料前驱体的热行为,确定了合成Li_2MnSiO_4/C复合正极材料的焙烧温度范围为600-800℃.X射线衍射(XRD)测试结果表明,不同温度下合成的样品材料均具有正交结构,且空间群为Pmn2_1,同时利用扫描电子显微镜(SEM)对所得样品材料的微观形貌及颗粒大小进行了表征.将所得Li_2MnSiO_4/C复合正极材料组装成扣式电池,并在不同的电流密度下进行充放电测试,结果表明:700℃合成的样品材料电化学性能最佳,具有较高的库仑效率及很好的循环稳定性.
As a new potential cathode material for lithium ion batteries,Li_2MnSiO_4/C was synthesized by a solution method.The thermal behavior of the precursor for Li_2MnSiO_4/C was measured by thermogravimetric (TG) analysis and the range of calcination temperatures from 600 to 800℃was determined.X-ray powder diffraction(XRD) patterns indicated that all the Li_2MnSiO_4/C samples crystallized in an orthorhombic structure with space group Pmn2_1.The morphology and particle size of the samples were also characterized by scanning electron microscopy(SEM).The effects of calcination temperature on the electrochemical performance of Li_2MnSiO_4/C were studied using galvanostatic charge-discharge measurements at various current densities.The results showed that the sample prepared at 700℃exhibited a much higher coulombic efficiency and better cyclic performance than the other samples.