Nitrogen-doped graphene-decorated FeSex-Sb2Se3/C nanofibers as advanced anode materials for potassium ion batteries

Abstract

Low operating voltage, high theoretical capacity conversion alloyed anodes ideal for potassium ion anodes. However, how to address the structural deformation and volume expansion of the changed alloyed materials throughout the reaction process is a crucial topic. A novel nitrogen-doped graphene-decorated FeSex-Sb2Se3/C nanofibers (FeSbSe-NGCNFs) composite is synthesized by adding dicyandiamide (DCDA) during electrospinning. Benefiting from porous one-dimensional nanostructure, graphene-decoration and rich nitrogen doping, the best electrochemical performance is shown by FeSbSe-NGCNFs when used as an anode in PIBs. FeSbSe-NGCNFs provide a reversible discharge specific capacity of 279.9 mAh/g at 100 mA g−1 after 100 cycles with a capacity retention of 87.6 %, in addition to a high capacity of 169.9 mAh/g at a high current of 3000 mA g−1. After 1000 cycles, the composite retained 115.8 mAh/g of capacity at 1000 mA g−1. The main causes of these exceptional cycling multiplicity properties are the porous structure that produces more carbon defects and active sites, increasing the amount of storage capacity for K+ and speeding up K+ transport and electron transfer, as well as the graphene nanosheet structure that enhances electrical conductivity and increases its specific surface area. Therefore, PIBs might benefit from the developed FeSbSe-NGCNFs as anode material.