One-pot synthesis of hierarchical Co1-xS/NC@MoS2/C hollow nanofibers based on one-dimensional metal coordination polymers for enhanced lithium and sodium-ion storage

Multicomponent metal sulfides have been recognized as promising anode materials for lithium/sodiumion storage given their enticing theoretical capacities. However, the simplification of synthetic processes and the construction of heterogeneous interfaces of multimetal sulfides remain great challenges. Herein, a hierarchical 1T-MoS2/carbon nanosheet decorated Co1-xS/N-doped carbon (Co1-xS/NC@MoS2/C) hollow nanofiber was designed and constructed via a one-pot hydrothermal method using a cobalt-based coordination polymer nanofiber. This nanofiber can transform in-situ into conductive N-doped carbon hollow fibers embedded with active Co1-xS nanoparticles, enabling the epitaxial growth of MoS2 nanosheets. Consequently, the Co1-xS/NC@MoS2/C composites achieve exceptional lithium/sodium-ion storage performance. Compared to MoS2/C microspheres and Co1-xS/NC hollow nanofibers alone, the Co1-xS/ NC@MoS2/C hollow nanofibers deliver higher discharge capacities (1085.9 mAh g(-1) for lithium-ion batteries (LIBs) and 748.5 mAh g(-1) for sodium-ion batteries (SIBs) at 100 mA g(-1)), better capacity retention (910 mAh g(-1) for LIBs and 636.5 mAh g(-1) for SIBs after 150 cycles at 100 mA g(-1)), and increased cycling stability (407.2 mAh g(-1) after 1000 cycles for SIBs at 1000 mA g(-1)). Furthermore, the kinetic analysis shows that the lithium/sodium-ion storage processes of the Co1-xS/NC@MoS2/C electrode are mainly controlled by pseudocapacitance behavior. The excellent electrochemical properties can thus be ascribed to the synergy of the MoS2/C nanosheets with the enlarged interlayer spacing, good conductivity of the carbon layers, and the Co1-xS nanoparticles embedded in the hollow nanofibers with extensive reaction sites. (C) 2020 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.