核壳结构MoO_x/C微球的制备及储锂性能

Preparation and Performance for Lithium Storage of Core-Shell-Structured MoO_x/C Microspheres

采用水热法合成了MoO3/酚醛树脂前驱体,然后在空气中进行煅烧处理,成功制备了一种新型核壳MoOx/C微球。对材料的晶体结构、形貌和元素价态进行分析表明,该材料的主要成分是单斜相MoO2、正交晶系MoO3和碳。树脂在空气中的煅烧碳化将MoO3/酚醛树脂前驱体中的六方晶系的MoO3还原为单斜相MoO2。其中少量的MoO2会在空气中重新被氧化成正交晶系的MoO3,形成了MoO2/MoO3异质结构。在这一系列反应的综合作用下,形成这种表面有裂纹的核壳MoOx/C微球复合材料。将该材料用作锂离子电池负极材料,表现出了循环稳定性高、倍率性能好等优异的电化学性能。在100mA·g^-1的电流密度下充放电循环100次之后,可逆容量达640.6mAh·g^-1。

Core-shell-structured MoOx /C microspheres were prepared through the calcination of a MoO3/resin precursor obtained by a hydrothermal method. Upon calcination, carbonized resin reduced hexagonal MoO3 into monoclinic MoO2. A small amount of monoclinic MoO2 was further oxidized to orthorhombic MoO3, forming coreshell MoOx /C microspheres. The hierarchical MoOx /C microspheres showed excellent electrochemical lithium storage performance when used as an anode material for lithium-ion batteries. High reversible capacities of 640.6 mAh· g^-1 was maintained at 100 mA·g^-1 after 100 cycles, demonstrating the high reversible capacity and excellent cycle performance of the MoOx /C microspheres for lithium storage.