Rationally designed hierarchical NiCo2O4-C@Ni(OH)2 core-shell nanofibers for high performance supercapacitors

Supercapacitor is considered as a favored candidate with promising future for next-generation energy storage applications. In quest of higher electrochemical performance, the integration of carbon-based and metallic-oxide-based materials becomes necessary. Herein, a creative yet effective design of one-dimensional hierarchical nanofibers, composed of a highly conductive core (NiCo2O4 embedded carbon fiber) and a sheath of Ni(OH)(2), is devised. The material is systematically fabricated by electrospinning and chemical bath deposition. Optimum electrode material exhibits high energy storage performance (1925 F g(-1) at 1 A g(-1)) and good cycling performance (retained 87% after 5000 cycles) compared to its counterpart without Ni(OH)(2) nanosheets (79% after 5000 cycles). Furthermore, the asymmetric supercapacitor assembled by this material and activated carbon delivers excellent specific capacitance performance (135 F g(-1) within 1.6V). Meantime, this asymmetric supercapacitor possesses high power density and energy density, up to 323 W kg(-1) and 48 Wh kg(-1), respectively, as well as outstanding rate capability, transcending most reported metal oxide carbon-based composite materials. (C) 2019 Elsevier Ltd. All rights reserved.