Solid-state fabrication of CNT-threaded Fe1-S@N-doped carbon composite as high-rate anodes for sodium-ion batteries and hybrid capacitors

Abstract

Abstract Metal sulfide/carbon composites have emerged as promising sodium-storage anode materials because of their decent theoretical capacities and low cost. Nevertheless, conventional metal sulfide/carbon nanocomposites are generally prepared via wet-chemical methods such as solvothermal routes, which is fussy and hard to scale up for mass production. Herein, we develop a facile solid-state method, in which a Fe1−xS@N-doped carbon composite threaded by CNTs (FS@NC@CNT) is prepared by directly annealing a ball-milled mixture containing iron (III) diethyldithiocarbamate complex and graphitized multi-walled CNTs. Highly dispersed Fe1-xS nanophase in N-doped carbon together with the highly conductive graphitized CNT networks greatly facilitate ion transport and electron transfer and thus promote the conversion reaction kinetics. The FS@NC@CNT composite exhibits competitive reversible capacity (440 mAh g−1 at 0.05 A g−1), excellent rate capacity (330 mAh g−1 at 10 A g−1), and good cyclic stability (86.5% capacity retention after 450 cycles at 7 A g−1). Coupled with Na3(VO0.5PO4) 2F2 @GO cathode, the full sodium-ion battery (SIBs) exhibits a high capacity retention of 98% after 80 cycles at 0.2 A g−1. Inspired by such excellent sodium storage performance in both half and full SIBs, the potential application of the composite in sodium-ion hybrid capacitors (SIHCs) is further studies by coupling with zeolite-templated carbon as a cathode. The SIHC device can maintain 80% capacity after 4500 cycles at 1 A g−1.