In-situ growth of graphene on carbon nanofiber from lignin

Design and synthesis of heterostructured carbon nanofibers is significant for applications in the field of optoelectronics, conductors and catalytic devices. Although lignin has been widely used as building blocks for fabricating nanofibers, it is still very challenging to synthesize conducting heterostructured carbon nanofibers without using additional catalysts. Herein, we first in-situ grew graphene grafted carbon nanofibers (G/CNFs) using calcium lignin sulfonate as starting materials without addition of catalysts. Through the electrospinning, pyrolysis and washing procedure, the as-spun nanofibers are converted into the flexible G/CNFs films. The in-situ formed CaS nanoparticles serve as catalysts for the growth of graphene on the surface of the CNFs, when the carbonization temperature is over 1100 °C. The as-prepared G/CNFs films exhibit superior electronic conductivity of 2377.9 S m−1, which is comparable to the values reported in the literature. As a proof-of-concept, the as-fabricated lithium-sulfur battery exhibits a high discharge of 808.7 mAh·g−1 after 600 cycles at 0.2 C by using the G/CNFs membrane as stand-alone and flexible sulfur cathode scaffolds. This work represents a promising new approach for designing heterostructured graphene/CNFs using low-cost lignin precursors, and provides significant insights for the sustainable development of CNFs in numerous applications.