Ultrathin carbon-coated Sb2Se3 nanorods embedded in 3D hierarchical carbon matrix as binder-free anode for high-performance sodium-ion batteries

Abstract

A high-performance freestanding anode composed of carbon-coated Sb2Se3 nanorods and conductive carbon matrix of reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs) for sodium-ion batteries (SIBs) is fabricated by a modified vacuum filtration, subsequent free-drying, and annealing. In this electrode architecture, the ultrathin amorphous carbon layers connect Sb2Se3 nanorods with the 3D interconnected carbon matrix. This unique cross-bonding network structure with good electrical conductivity and volume buffering effect improves the structural stability during repeating Na+ insertion/extraction and electrochemical performance. As a binder-free anode for SIBs, it reveals preferable initial charge-specific capacity of 792 mA h g−1 at a current density of 100 mA g−1, and simultaneously sustains 100 cycles at 500 mA g−1 with a specific capacity of 485 mA h g−1, and capacity retention ratio of 90%. The flexible Sb2Se3-based material as an anode can expectantly apply to the further development of advanced low-cost and flexible electronics for SIBs.