Hetero-structure arrays of NiCoO2 nanoflakes@nanowires on 3D graphene/nickel foam for high-performance supercapacitors

Stable and enhanced electrochemical performance based on hierarchical core-shell structure of CoMn2O4@Ni3S2electrode for hybrid supercapacitor

Herein, accessible and low-cost CoMn₂O₄@Ni₃S₂core-shell nanoneedle arrays have been prepared via a two-step approach comprised with hydrothermal-calcination and electrochemical deposition procedures, successfully. In the beginning, CoMn₂O₄nanoneedle arrays took root on Ni foam to form the core skeleton and subsequently, hierarchical Ni₃S₂nanosheets uniformly overlaid on the surface of CoMn₂O₄nanoneedles shaping the shell structure. This CoMn₂O₄@Ni₃S₂material was measured directly as supercapacitor electrode and presented high specific capacity of 192.2 mAh g^-1with current density of 1 A g^-1. Besides, the electrode delivered outstanding cyclical stability as the capacity retention attained 90.2% after charge-discharge measurement at a large current density of 10 A g^-1for 10 000 cycles. Furthermore, a hybrid supercapacitor assembled by CoMn₂O₄@Ni₃S₂cathode and activated carbon anode represented a high energy density of 51.2 Wh kg^-1with the power density of 1030.0 W kg^-1. This work shows a facile and inexpensive procedure to design high-performance and strong-stability supercapacitor electrodes.

Emerging of Heterostructure Materials in Energy Storage: A Review

With the ever-increasing adaption of large-scale energy storage systems and electric devices, the energy storage capability of batteries and supercapacitors has faced increased demand and challenges. The electrodes of these devices have experienced radical change with the introduction of nano-scale materials. As new generation materials, heterostructure materials have attracted increasing attention due to their unique interfaces, robust architectures, and synergistic effects, and thus, the ability to enhance the energy/power outputs as well as the lifespan of batteries. In this review, the recent progress in heterostructure from energy storage fields is summarized. Specifically, the fundamental natures of heterostructures, including charge redistribution, built-in electric field, and associated energy storage mechanisms, are summarized and discussed in detail. Furthermore, various synthesis routes for heterostructures in energy storage fields are roundly reviewed, and their advantages and drawbacks are analyzed. The superiorities and current achievements of heterostructure materials in lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), lithium-sulfur batteries (Li-S batteries), supercapacitors, and other energy storage devices are discussed. Finally, the authors conclude with the current challenges and perspectives of the heterostructure materials for the fields of energy storage.

Investigation of the Electrochemical Properties of Ni0.5Zn0.5Fe2O4 as Binder-Based and Binder-Free Electrodes of Supercapacitors

In this work, Ni0.5Zn0.5Fe2O4 is synthesized as binder-based (NZF) and binder-free electrodes (NZF@NF). The binder-free electrode is directly synthesized on nickel foam via facile hydrothermal techniques. The crystalline phase of both of these electrodes is examined through X-ray diffraction. Their morphology is investigated by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (TEM), which revealed the well-defined nanostructure with the shape like thin hexagonal platelets. The chemical composition is verified by energy dispersive spectroscopy (EDS). Their electrochemical properties are analyzed by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). The NZF@NF electrode has outperformed the binder-based NZF electrode in terms of electrochemical performance owing to the 3D interconnected structure of the nickel foam. The NZF@NF electrode has delivered a high specific capacity of 504 F g−1 at the current density of 1 A g−1, while its counterpart has delivered a specific capacity of 151 F g−1 at the same current density.

Controlled synthesis of a hierarchical CuNi2O4@SnS nanocauliflower-like structure on rGO as a positive electrode material for an asymmetric supercapacitor

Hierarchical CuNi2O4@SnS@rGO/NF is a promising electrode material for building up an impressive supercapacitor.

Free-standing NiCoSe2 nanostructure on Ni foam via electrodeposition as high-performance asymmetric supercapacitor electrode

Designing a high-energy-density and power-density electrode for supercapacitors has become an increasingly important concept in the energy storage community. In this article, NiCoSe₂ nanostructures were electrodeposited on nickel (Ni) foam and directly used as electrodes for supercapacitors. The effect on the morphology and electrochemical performance of NiCoSe₂ prepared under different scan rates was measured through scanning electron microscopy and various electrochemical measurements. The resultant NiCoSe₂ prepared with 5 mV s^-1 exhibits a cross-linked porous nanostructure and a high specific capacitance of 2185 F g^-1 at a current density of 1 A g^-1. Taking advantage of these features, an ASC is constructed by using NiCoSe₂ on Ni foam as the positive electrode and an active carbon electrode as the negative electrode with 3 M KOH as the electrolyte. The ASC displays a high-energy density of 41.8 Wh kg^-1, an ultrahigh power output of 8 kW kg^-1, as well as a long cycling life (91.4% capacity retention after 10 000 cycles). The excellent electrochemical performance makes the porous NiCoSe₂ nanostructures a promising alternative in energy storage devices.

Preparation of mesoporous CoNiO2 hexagonal nanoparticles for asymmetric supercapacitors via a hydrothermal microwave carbon bath process

Mesoporous CoNiO₂ hexagonal nanoparticles prepared via a hydrothermal microwave carbon bath process instead of the conventional calcination method have excellent pseudocapacitance properties.