Synthesis of MoS2@N-MXene/C Heterogeneous Nanosheets and its Enhanced Pseudocapacitance Effects for NIBs

Graphical NIB news : MoS 2 anchored on nitrogen-doped MXene nanosheets with carbon coating were prepared and applied in Na-ion batteries (NIBs). It remained at ∼308 mAh g −1 at 0.5 A g −1 after 300 cycles and showed higher rate performance of ∼189 mAh g −1 at 4 A g −1 . The MoS 2 @N-MXene/C heterogeneous nanosheets showed enhanced pseudocapacitance effects of 84.5 % at a scan rate of 2 mV s −1 according to CV curves simulation. Currently, Na-ion batteries (NIBs) have emerged as a new generation of energy storage devices. However, due to the lack of suitable anode materials, the large-scale practical application of NIBs is still greatly limited. Therefore, to address this issue, an effective strategy towards an advanced NIBs anode was developed by achieving MoS 2 anchored on nitrogen-doped MXene nanosheets with carbon coating (shorten as MoS 2 @N-MXene/C). The structure, surface chemistry state and micromorphology of MoS 2 @N-MXene/C were carefully analyzed and characterized by XRD, XPS and SEM/TEM, respectively. It was shown that MoS 2 was loaded on N-MXene to form a heterogeneous nanosheets structure. When applied to the anode of NIBs, MoS 2 @N-MXene/C delivered ∼189 mAh g −1 at 4 A g −1 and remained at ∼308 mAh g −1 after 300 cycles at 0.5 A g −1 . Moreover, based on the simulation and calculation from CV curves, the enhanced electrochemical performances of MoS 2 @N-MXene/C was assigned to its high pseudocapacitance-dominated contribution (84.5 % at a scan rate of 2 mV s −1 ). Therefore, owing to the highly conductive N-MXene and the actively anchored MoS 2 , MoS 2 @N-MXene/C could effectively provide efficient channels for charge transfer and ionic diffusion. The presented design strategy may provide a guidance for developing more-efficient NIBs anode.