采用多元醇法合成Li2MnSiO4/C复合材料:将Si(OC2H5)4、LiAc·2H2O、Mn(Ac)2·4H2O在乙二醇中196℃回流16h，沉淀物过滤、干燥以后与蔗糖混合并在500、600和700℃分别加热10h,自然冷却到室温.利用X射线衍射、元素分析、场发射扫描电镜、高分辨透射电镜等手段对合成样品进行表征.Rietveld精修表明，合成样品中存在两种Li2MnSiO4相，空间群分别为Pmn21和P121/n1，还有Li2SiO3杂相.FESEM观察显示当热处理温度从500℃升高至700℃时，样品的颗粒粒径从5~20nm提高到20~40nm.Li2MnSiO4/C复合材料中的碳分布是均匀的.HRTEM分析表明在Li2MnSiO4颗粒上包覆有一层无定型的碳薄膜.电化学性能测试表明，在600℃保温10h得到的样品具有最佳的电化学性能，首次放电容量达到132.4mAh/g，10次循环后容量保持率为80%.
The Li2MnSiO4/C composite was synthesized through a polyol process following by heattreatment at intermediate temperatures. The precursors were precipitated from Si(OC2H5)4, LiAc·2H2O and Mn(Ac)2·4H2O in ethylene glycol by refluxing at 196℃ for 16h, the dried powders were milled, pressed and heat-treated at 500℃, 600℃ and 700℃ for 10h. The obtained samples were characterized by X-ray diffraction, automatic elemental analyzer, field emission scanning electron microscope (FESEM), energy dispersive spectroscope (EDS), and high resolution transmission electron microscope (HRTEM). As a result of the Rietveld refinement, two possible Li2MnSiO4 forms crystallizing in Pmn21 and P121/n1 space groups, respectively, are considered as the major phases, and Li2SiO3 is identified as the impurity phase. According to the FESEM observation, the mean particle size increases from 5-20nm to 20-40nm as the heattreatment temperature increasing from 500℃ to 700℃. Carbon is homogenously distributed on the prepared Li2MnSiO4/C composites. The HRTEM examination confirms that the Li2MnSiO4 particles are surrounded by a very thin amorphous carbon layer. The electrochemical experiments reveal that the Li2MnSiO4/C composite heat-treated at 600℃ for 10h has the higher electrochemical performance with an initial discharge capacity of 132.4mAh/g and a capacity retention ratio of 80% at the tenth cycle.
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