Direct Growth of Ultrathin NiCo2O4/NiO Nanosheets on SiC Nanowires as a Free-Standing Advanced Electrode for High- Performance Asymmetric Supercapacitors

摘要

In this paper, we successfully employed SiC nanowires (SiC NWs) with splendid anticorrosion, antioxidation, heat-resistant properties, excellent conductivity, and large specific surface area directly deposited on carbon cloth (CC) as scaffolds to grow first the loose, porous and ultrathin NiCo2O4/NiO nanosheets (NiCo2O4/NiO NSs) via a facile hydrothermal technology coupled with annealing treatment to form a free-standing and stable hybrid electrode for asymmetric supercapacitor (ASC). Benefiting from the smart combination of SiC NWs and NiCo2O4/NiO NSs, illustrating a promising synergistic strategy, the electrode delivered an ultrahigh specific capacitance of 1801 F g~(-1)at 1 mA cm~(-2) as well as a remarkable rate capability of 1499 F g~(-1)at 10 mA cm~(-2). Furthermore, the additive-free functionalized SiC NWs@NiCo2O4/NiO NSs on CC acted as the positive electrode, assembled with the activated carbon (AC) on nickel foam (NF) negative electrode to fabricate an advanced ASC with intriguing electrochemical performances in terms of huge energy density (60 Wh kg~(-1)at 1.66 kW kg~(-1)) in addition to exceptional cycling stability (90.9% capacitance retention after 2000 cycles). This novel strategy can not only further widen the application of SiC NWs-based materials but also provide new insight into the development of next-generation supercapacitors with high energy/power densities.