A freestanding nitrogen-doped carbon nanofiber/MoS2 nanoflowers with expanded interlayer for long cycle-life lithium-ion batteries

Abstract

In this work, a 3D flexible freestanding nitrogen-doped carbon nanofiber/MoS2 nanoflowers (NCNFs/MoS2) network with expanded interlayer spacing is fabricated by facile electrospinning and hydrothermal synthesis method, which is employed as flexible free-standing anodes for lithium-ion batteries (LIBs) without any additives. A poly(acrylonitrile-co-β-methylhydrogen itaconate) copolymer is synthesized and uses as a precursor to improve the conductivity and flexibility of NCNFs. The three-dimensional open structure of NCNFs/MoS2 provides a highly conductive pathway for fast transfer of charge and electron, and expanded interlayer spacing of MoS2 nanoflowers can increase available surface active sites for Li-ion and reduce the obstacle of Li-ion migration during lithiation/delithiation process. Moreover, it can relieve large internal stress and accommodates volume change during cycling. The NCNFs/MoS2 composite delivers a high capacity of 1168.6 mA h g−1 at a current density of 5A g−1 and an excellent reversible capacity retention of 94.49% after 1000 cycles (only 0.055‰ decay per cycle), which makes it one of the highest capacities and best cycling stability ever reported to date. It also exhibits a superior rate capacity of 909.5 mA h g−1 at current densities 10A g−1, indicating the 3D flexible freestanding NCNFs/MoS2 composite network has potential application in high-performance lithium-ion batteries.