Solvent Induced Activation Reaction of MoS2 Nanosheets within Nitrogen/Sulfur-Codoped Carbon Network Boosting Sodium Ion Storage.

ABSTRACT

MoS2 , as a classical 2D material, becomes a capable anode candidate for sodium-ion batteries. However, MoS2 presents a disparate electrochemical performance in the ether-based and ester-based electrolyte with unclear mechanism. Herein, tiny MoS2 nanosheets embedded in nitrogen/sulfur-codoped carbon (MoS2 @NSC) networks are designed and fabricated through an uncomplicated solvothermal method. Thanks to the ether-based electrolyte, the MoS2 @NSC shows a unique capacity growth in the original stage of cycling. But in the ester-based electrolyte, MoS2 @NSC shows a usual capacity decay. The increasing capacity puts down to the gradual transformation from MoS2 to MoS3 with the structure reconstruction. Based on the above mechanism, MoS2 @NSC demonstrates an excellent recyclability and the specific capacity keeps around 286 mAh g-1 at 5 A g-1 after 5000 cycles with an ultralow capacity fading rate of only 0.0034% per cycle. In addition, a MoS2 @NSC‖Na3 V2 (PO4 )3 full cell with ether-based electrolyte is assembled and demonstrates a capacity of 71 mAh g-1 , suggesting the potential application of MoS2 @NSC. Here the electrochemical conversion mechanism of MoS2 is revealed in the ether-based electrolyte and significance of the electrolyte design on the promoting Na ion storage behavior is highlighted.