Effect of different shell structure on lithium storage properties of MoS2 anode

MoS2, with a high theoretical specific capacity (670 mAh/g), is a good alternative to traditional graphite as anode for lithium ion batteries (LIBs). Poor conductivity and serious volume expansion during charging and discharging process, however, result in poor cycle performance and rate performance of MoS2 anode for LIBs. Here, the TiO2 coated in mesosphere-petal-like shell (MPLS) structure of MoS2 (TiO2@MoS2) and MoS2 encapsulated in hollow mesoporous carbon spheres shell (HMCSS) structure (MoS2@C) are obtained, and effect of different shell structure on lithium storage properties of MoS2 are investigated. The results show that MoS2@C exhibits higher discharge capacity, better rate capability and cycling performance than TiO2@MoS2 and pure MoS2. The significantly enhanced charge and discharge performance of MoS2@C can be attributed to the improvement of electric conductivity and the inhibition of volume expansion result from the introduction of HMCSS structure. Also, TiO2@MoS2 demonstrates remarkable lithium storage performance in comparison with pure MoS2, which is ascribe to MPLS structure of MoS2 assembled from corresponding 2D nanosheets that facilitates the penetration of electrolyte and provides more sites to accommodate Li+, and which is also attribute to TiO2 as effective mechanical support and thus alleviate volume expansion and aggregation of MoS2 during charging and discharging process. It is believed that the different shell structure used in MoS2 provides a novel approach to enhance the lithium storage performance of metal sulfide.