轻度剥离二硫化钼/石墨烯复合材料的制备及其电化学储锂性能

Syntheis and electrochemical performance of slightly exfoliated MoS_2 /graphene composite for lithium storage

为了增强MoS2的电化学储锂性能,将轻度剥离的商业MoS2与氧化石墨烯悬浮液混合,用液相还原法制备了轻度剥离MoS2/石墨烯复合材料,并对其微观结构和形貌进行了表征。结果表明轻度剥离MoS2的层数明显减少,其表面产生了许多裂纹,复合材料中轻度剥离的MoS2与石墨烯能较好地复合在一起。电化学测试表明与商业化MoS2比,轻度剥离MoS2/石墨烯复合材料具有更高的电化学储锂容量(1 022mAh/g),更好的循环稳定性能和显著增强的充放电倍率性能。电化学阻抗测试表明石墨烯显著降低了电极反应过程中的电子转移电阻。电化学储锂性能的增强主要是由于轻度剥离MoS2层数的明显减少及其表面的许多裂纹,以及轻度剥离MoS2与石墨烯之间的相互协同作用。电化学阻抗测试证明了石墨烯显著增强了复合电极材料的导电性能和电化学贮锂过程中电子传递能力。

In order to improve the electrochemical performance of MoSe for lithium storage, the slightly exfoliated MoS2/graphene composite has been synthesized by a liquid phase reduction method employing slightly exfoiatiated commercial MoS2 and graphene oxide sheets as starting materials. The microstructure and morphology of the samples are characterized by X-ray diffraction （XRD）, transmission electronic microscopy （TEM） and scanning electronic microscopy （SEM）. It is found that there are many cracks existing in the slightly exfoiatiated MoS2 surface, which offer more channels {or Li-ion insertion/extraction. In the com- posite, the slightly exfoiatiated MoSz sheets are well combined with graphene. The electrochemical measurement demonstrates that the exfoliated MoSe/graphene composite exhibits higher reversible capacity （1 022 mAh/g） with excellent cycling perform- ance and significantly enhanced high-rate capability compared to MoSe. The electrochemical impedance test indicates that the incorporation of graphene greatly reduces the eletron-transfer resistance of electrode reaction~ The significant improvement in electrochemical perfromance could be atrributed to the crack-rich surface structure of exfoliated MoS2 and the synergic interaction between exfoiated MoSv and graphene. In addition, the electrochemical impedance spectra demonstrate that graphene greatly en hances the conductivity and charge-transfer of the composite electrode for the electrochemical lithium storage.