Sputtered nickel oxide-coated porous carbon nanofibers as binder-free anodes for high-performance lithium-ion batteries.

A binder-free anode for high-performance lithium-ion batteries consisting of NiO uniformly coated on porous carbon nanofibers (FCNF) was successfully fabricated. The NiO was formed on the FCNF surface through a two-step process involving radio frequency magnetron sputtering of Ni followed by thermal oxidation. The obtained NiO/FCNF composite electrode eliminates the need for binders and conductive additives, simplifying electrode preparation and increasing the active material loading. The electrode has been characterized by using scanning electron microscopy, surface area analysis, X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, and Raman spectroscopy. The NiO/FCNF anode provided a high discharge capacity of 884 mAh g-1 and a charge capacity of 858 mAh g-1 after 100 cycles at a current density of 100 mA g-1. Furthermore, the composite electrode displayed good rate performance, retaining a specific capacity of 444 mAh g-1 even at a high current density of 3 A g-1. The enhanced performance is attributed to the synergistic effects of the components: the FCNF network provides excellent electrical conductivity and a robust scaffold that accommodates the volume changes of NiO during cycling, while the uniformly coated NiO offers high theoretical capacity. This work highlights a promising approach for developing high-performance, free-standing anodes for next-generation LIBs.