PVD amorphous carbon coated 3D NiCo2O4 on carbon cloth as flexible electrode for both sodium and lithium storage.

With the advent of flexible electronics, flexible secondary rechargeable batteries have attracted considerable attentions as a promising power source in the new generation of flexible electronics such as roll-up displays, smart electronics, and implantable medical devices. In this work, we report the fabrication of 3D NiCo 2 O 4 arrays on carbon cloth as a binder-free anode for sodium/lithium ion storage. Amorphous carbon layer is used to modify the surface of NiCo 2 O 4 arrays by physical vapor deposition (PVD). The electrochemical performance measurements demonstrate that the amorphous carbon layer can improve the electrochemical stability of NiCo 2 O 4 . The NiCo 2 O 4 @ C/carbon cloth electrode exhibits a high reversible capacity of 749.9 mAh g −1 , stable cycling with more than 535.47 mAh g −1 at 500 mA g −1 over 100 cycles and impressive rate capability (318 mAh g −1 at 5 A g −1 over 700 cycles) for SIBs and excellent electrochemical performance for LIBs (reversible capacity of 807.63 mAh g −1 were observed for 100 cycles). [ABSTRACT FROM AUTHOR]