Carbon-coated MoS2 nanosheets@CNTs-Ti3C2 MXene quaternary composite with the superior rate performance for sodium-ion batteries

The exploration of advanced MoS2-based electrode materials overcoming their inherent low conductivity and large volume changes is of importance for next-generation energy storage. In this work, we report a simple and high-efficient one-pot hydrothermal approach to prepare a unique and stable 1D/2D heterostructure. In the architecture, ultrathin carbon layer-coated MoS2 nanosheets with large expanded interlayer of 1.02 nm are vertically grown onto the Ti3C2 MXene and cross-linked carbon nanotubes (CNTs), giving rise to a highly conductive 3D network. The interlayer expanded MoS2 nanosheets can greatly facilitate the Na ions/electrons transmission. Meanwhile, the N-doped 1D/2D CNTs-Ti3C2 matrix can be used as a strong mechanical support to well relieve the large volume expansion upon cycles. As a combination result of several advantages, the developed quaternary C-MoS2/CNTs-Ti3C2 composite anode shows an excellent sodium storage performance (562 mA h g−1 at 100 mA g−1 after 200 cycles) and rate capability (475 mA h g−1 at 2000 mA g−1). The density functional theory calculations further prove that the full combination of layer-expanded MoS2 nanosheets and N-doped Ti3C2 matrix can significantly enhance the adsorption energy of Na ions, further resulting in the enhancement of sodium storage capabilities.