一锅法合成基于一维金属配位聚合物的Co1–xS/NC@MoS2/C多层中空纳米纤维及其储锂/储钠性能

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

开发优异储锂/储钠性能的新型负极材料对现有电池系统的发展至关重要.因其高的理论容量,多组分金属硫化物被认为是有潜力的锂/钠离子电池负极材料.然而,合成工艺的简化和金属硫化物间异质界面的构建仍然面临巨大挑战.本文通过一锅水热法,以一维的钴/次氮基三乙酸配位聚合物纳米纤维为前驱体,构建了一种1T-MoS2/碳纳米片修饰的含Co1–xS纳米颗粒的氮掺杂多层中空碳纤维(Co1–xS/NC@MoS2/C). Co1–xS/NC中空纤维的形成与MoS2的生长同时进行;MoS2纳米片修饰的中空纤维可提供丰富的活性表面并缩短离子扩散路径,有利于电子传输和锂/钠离子扩散;同时, MoS2和Co1–xS周围形成的碳基体,不仅有利于结构的完整性和导电性,而且避免了活性物质与电解质的直接接触. Co1–xS/NC@MoS2/C作为锂/钠离子电池负极材料,展现出优异的倍率性能和循环寿命.本文为多维异质纳米复合材料的构建提供了潜在的方法.

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 m A 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.