Flexible Sb-graphene-carbon nanofibers as binder-free anodes for potassium-ion batteries with enhanced properties.

ABSTRACT

Potassium-ion batteries (KIBs) are emerging as attractive alternatives to lithium-ion batteries for the large scale energy storage and conversion systems, in view of the natural abundance and low cost of potassium resources. However, the lack of applicable anodes for reversible accommodation to the large K+ limits the application of KIBs. Herein, porous Sb-graphene-carbon (Sb-G-C) nanofibers are fabricated via a scalable and facile electrospinning approach. As an attempt, the nanofibers weaving into flexible mats are introduced as binder-free anode materials of KIBs, presenting a great cycle life (204.95 mAh g-1 after 100 cycles at 100 mA g-1), as well as the excellent rate capability (120.83 mAh g-1 at 1 A g-1). The superior performances of the Sb-G-C anodes can be derived from the dispersed graphene, which offers enhanced tolerance to the volume change and promotes the electron transportation, accounting for the outstanding cyclability and rate capability. Furthermore, the extrinsic pseudocapacitance created from the 1D porous nanostructure of the Sb-G-C also boosts the K+ storage capacity. The presented results may pave a new pathway for future high-performance KIBs.