Metal-organic frameworks-derived porous NiCo2O4/carbon composite nanofibers as anodes for Li/Na-ion batteries

The NiCo2O4 anode has high theoretical specific capacity for Li/Na-ion batteries, but the low conductivity and volume expansion during lithiation and delithiation lead to severe capacity fading. In this study, a porous bead-like NiCo2O4/carbon composite nanofiber with a metal-organic frameworks (MOFs) structure is prepared by tuning the ratio of polyacrylonitrile (PAN) during the electrospinning process. The MOF-derived NiCo2O4 particles were firmly anchored on highly conductive carbon nanofibers, generating the sturdy construction and large specific surface area (169.7 m2/g) of NCO/C-12. Owing to these structural merits, more active sites are provided with accelerated electron/Li-ion transport upon cycling, and consequently the NCO/C-12 delivered a promoted cycling stability and synergistically enhanced rate performance. The reversible discharge capacity of 1125 mAh/g after 200 cycles and excellent rate performance of 695 mAh/g at 1.5 A/g are presented. And the NCO/C-12 electrode still kept its morphology and excellent structural stability without significant volume expansion or pulverization even after 200 cycles. When serving as anode materials for sodium-ion batteries (SIBs), the electrode also exhibited excellent cycling and rate performance.