In-situ formation of Co1-xS hollow polyhedrons anchored on multichannel carbon nanofibers as self-supporting anode for lithium/sodium-ion batteries

The exploration of prospective electrode materials represents great challenges for remarkable lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). Herein, we report a reliable synthetic approach for the in-situ growth of the Co-based zeolitic imidazolate framework (ZIF-67) on electrospun nanofibers, followed by carbonization and sulfurization with the formation of free-standing Co1-xS hollow polyhedrons anchored on multichannel carbon nanofibers (Co1-xS/MCF) for LIBs and SIBs. The Co1- xS/MCF electrode displays a high reversible capacity (813 mAh g-1 over 180 cycles at 0.1 A g-1), and stable cycle performance (559 mAh g-1 for 300 cycles at 1 A g-1) in LIBs. For SIBs, Co1-xS/MCF electrode exhibits a favorable Na-storage capacity (433 mAh g-1 over 120 cycles at 0.1 A g-1). The as-prepared binder-free Co1- xS/MCF anode demonstrates the advanced electrochemical properties for LIBs and SIBs. It is attributed to the particular multichannel nanostructure and the Co1- xS hollow polyhedrons (Co1-xS HPs), which provide enough active sites, and the internal void space effectively reduces the structural strain and eases the volume expansion to maintain structural integrity. This work gives insights to design a unique structure for promising LIBs and SIBs.