重新堆积和钴离子掺杂的MoS_2负极材料的合成与性能研究

Synthesis and characterization of restacked and cobalt-doped MoS_2 as anode materials for lithiumion batteries

以原料MoS2为前驱体,经正丁基锂剥离和水热处理,制备出重新堆积的MoS2和钴离子掺杂的MoS2.利用XRD、TEM、SEM和EDS等分析手段对样品的形貌和化学组成进行表征.结果表明:重新堆积的MoS2和钴离子掺杂的MoS2的晶型均为2H-MoS2,但结晶度都比原料的差.重新堆积的样品的组成仍为MoS2,Co2+掺杂的样品的组成为Co0.39MoS2.重新堆积的MoS2由较规则的纳米片组成,片厚20～30nm.钴离子掺杂的MoS2也由纳米片或纳米棒组成,片厚20～40nm.把原料、重新堆积的MoS2、钴离子掺杂的MoS23种材料作为锂离子电池负极材料,对其电化学性质进行初步测试,实验发现:重新堆积的MoS2具有很高的比容量和很好的循环稳定性,钴离子掺杂的MoS2循环稳定性优于原料,但比重新堆积的MoS2差.

Restacked MoS2 and cobalt doped MoS2 were synthesized by an approach involving exfoliation, intercalation, and the hydrothermal process, using raw MoS2 as the precursor and nbutyllithium as the exfoliating reagent. The samples were characterized by X-ray powder diffraction （XRD）, transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, and energy dispersive X-ray spectroscopy （EDS）. XRD results showed that the crystal phase of the restacked MoS2 and cobalt-doped MoS2 could be assigned to 2H-MoS2. TEM and SEM images showed that the raw sample consisted of irregular particles, the restacked and cobalt-doped MoS2 mainly consisted of nanoflakes with a thickness 20--30 nm and 20--40 nm, respectively. EDS results indicated that the chemical formula of restacked and cobah-doped samples were MoS2 and Coo. 39Mo82 , respectively. The lithiumion charge/discharge behavior of the electrodes used the samples as active material was measured. Compared to the raw MoS2 electrode, the restacked MoS2 exhibited highreversible lithium storage capacity and superior rate capability. The charge/discharge capacities of the cobalt-doped MoS2 electrode were lower than those of the restacked MoS2, though they were higher than those of the raw MoS2. The reasons why the restacked and the cobalt-doped MoS2 electrodes had better electrochemical performances than the raw MoS2 electrode had been discussed briefly.