FeCoS2 polyhedral spherical nanoparticle decorated nitrogen doped hollow carbon nanofibers as high-performance self-supporting anodes for K-ion storage

Herein, we present a freestanding and flexible 3D nanocomposite made of polyhedral spherical FeCoS2 and nitrogen-doped hollow carbon nanofibers (FeCoS2@N-HCNFs) that is synthesized through coaxial electrospinning, high-temperature calcination, and a facile solvothermal process. As a binder-free anode composite for potassium-ion batteries (PIBs), FeCoS2@N-HCNF presents a high specific discharge capacity on the first lap (701.2 mA h g(-1) at 100 mA g(-1)) and superior cycling stability (132.6 mA h g(-1) at 3200 mA g(-1) after 600 cycles). The impressive electrochemical performance can be ascribed to the unique 3D structure, such as the enormous specific surface area of the mesoporous structure beneficial for K+ transfer, the three-dimensional hollow carbon nanofiber scaffold enhances the structural stability, and polyhedral spherical FeCoS2 improves the overall specific capacity. According to the above description, the FeCoS2@N-HCNF anode is a promising candidate for advanced potassium-ion batteries.

Automated summary

In this study, a freestanding and flexible 3D nanocomposite FeCoS2@N-HCNF is synthesized through coaxial electrospinning, high-temperature calcination, and a facile solvothermal process. As a binder-free anode composite for potassium-ion batteries, FeCoS2@N-HCNF exhibits high specific discharge capacity and superior cycling stability. The unique 3D structure and polyhedral spherical FeCoS2 are responsible for the impressive electrochemical performance.