Core-Shell Carbon Nanofibers@Ni(OH)2/NiO Composites for High-Performance Asymmetric Supercapacitors

Abstract

The application of transition metal oxides/hydroxides in energy storage has long been studied by researchers. In this paper, the core-shell CNFs@Ni(OH)2/NiO composite electrodes were prepared by calcining carbon nanofibers (CNFs) coated with Ni(OH)2 under an N2 atmosphere, in which NiO was generated by the thermal decomposition of Ni(OH)2. After low-temperature carbonization at 200 °C, 250 °C and 300 °C for 1 h, Ni(OH)2 or/and NiO existed on the surface of CNFs to form the core-shell composite CNFs@Ni(OH)2/NiO-X (X = 200, 250, 300), in which CNFs@Ni(OH)2/NiO-250 had the optimal electrochemical properties due to the coexistence of Ni(OH)2 and NiO. Its specific capacitance could reach 695 F g−1 at 1 A g−1, and it still had 74% capacitance retention and 88% coulomb efficiency after 2000 cycles at 5 A g−1. Additionally, the asymmetric supercapacitor (ASC) assembled from CNFs@Ni(OH)2/NiO-250 had excellent energy storage performance with a maximum power density of 4000 W kg−1 and a maximum functional capacity density of 16.56 Wh kg−1.

Core–Shell Structured Carbon Nanofiber-Based Electrodes for High-Performance Supercapacitors

“…The hydrothermal reaction temperature was 120 °C, and the reaction time was 6 h. Finally, the samples fabricated were subjected to low-temperature carbonization in a N 2 atmosphere at 250 °C for 1 h, with a heating rate of 5 °C min −1 , thus obtaining the CHO composite. The preparation method was also described in our previously reported paper [ 12 , 30 ].…”

“…In this study, by combining multiple materials to compensate for each other’s shortcomings and designing their structures reasonably, a multistage core–shell composite electrode material with excellent performance for supercapacitors was fabricated. In our previous work, a composite electrode combining Ni(OH) 2 , NiO, and carbon nanofibers (CNFs) (CNFs@Ni(OH) 2 /NiO-250) was obtained which demonstrated good electrochemical properties [ 12 ]. In this work, to further enhance the electrochemical performance of CNFs@Ni(OH) 2 /NiO-250 (CHO), five transition metal sulfides (XS, X = Mn, Co, Fe, Cu, and Ni) were loaded onto its surface, using hydrothermal growth for 5 h to obtain electrode materials loaded with XS (CHO/XS-5h) and determine the optimal sample as CHO/NiS-5h.…”

Boron Carbide as an Electrode Material: Tailoring Particle Morphology to Control Capacitive Behaviour

“…Thus, good electrically conductive materials with a high surface area are desired to achieve high capacitance values of EDLCs. In this respect, carbon-based materials with varying morphologies, such as nanosheets, nanotubes, and fibers, have been comprehensively investigated for EDLCs [ 13 , 14 , 15 , 16 , 17 ]. On the other hand, capacitance generation in pseudocapacitors are based on reversible Faradaic processes [ 18 ].…”

“…Nevertheless, they are typically limited by their low energy densities [ 19 ]. Conducting polymers and transition metal oxides, such as MnO 2 , NiO, Co 3 O 4 , and ZnO, are commonly used electrode materials in pseudocapacitors [ 3 , 14 , 20 , 21 ]. In addition to these materials, recent studies show that polyoxometalate materials are also promising electrode materials for pseudocapacitors [ 8 , 22 , 23 ].…”

Fabrication of 3D HierarchicalSphericalHoneycomb-Like Nd2O3/Co3O4/Graphene/Nickel Foam Composite Electrode Material for High-Performance Supercapacitors

“…With the development of the economy and society, people’s dependence on energy has been increasingsince about the Industrial Revolution. These energy sources cannot be separated from the extraction and consumption of fossil fuels [ 1 , 2 ], and it is sure to happen that rapid economic development has brought serious environmental pollution at the same time [ 3 , 4 ]. However, as sustainable energy sources such aswind and solar are easily impacted by location and time, urgent research and development into novel energy storage technologies are required [ 5 ].…”