Facile fabrication of Ni0.85Se nanowires by the composite alkali salt method as a novel cathode material for asymmetric supercapacitors

Effects of chemical composition and vacant oxygen defects on the performance of Ni(OH)2–Ni0.85Se heterostructure nanowires as supercapacitor electrodes

The research focus of supercapacitors is the composition and structural design of electrode materials.

Facile One-Step Microwave-Assisted Method to Synthesize Nickel Selenide Nanosheets for High-Performance Hybrid Supercapacitor

Nanosheets structures can be employed as the most promising electrode material to enhance electrochemical performance for supercapacitors. Nickel Selenide (Ni_0.85Se) nanosheets are synthesized using a rapid microwave synthesis method in a single step. The Ni_0.85Se nanosheets possess a high surface area (125 m²g^-1) with a hexagonal crystalline structure. It shows magnificent electrochemical properties, such as splendid specific capacitance (2530 Fg^-1 at 0.5 Ag^-1). An asymmetric hybrid supercapacitor is fabricated with nickel selenide nanosheets as a positive electrode and activated carbon as a negative electrode. The assembled hybrid supercapacitor displays a high energy density of 63.5 WhKg^-1 at a power density of 404 WKg^-1, and after 8000 cycles, only 5% capacitance is lost along with the better voltage window at 0-1.6 V.

Synthesis of bimetallic nickel cobalt selenide particles for high-performance hybrid supercapacitors

Supercapacitors are known as promising excellent electrochemical energy storage devices because of their attractive features, including quick charge and discharge, high power density, low cost and high security. In this work, a series of litchi-like Ni-Co selenide particles were synthesized via a simple solvothermal method, and the Ni-Co compositions were carefully optimized to tune the charge storage performance, charge storage kinetics, and conductivity for battery-like supercapacitors. Interestingly, the optimal sample Ni0.95Co2.05Se4 exhibits a high capacity of 1038.75 F g-1 at 1 A g-1 and superior rate performance (retains 97.8% of the original capacity at 4 A g-1). Moreover, an asymmetric supercapacitor device was assembled based on the Ni0.95Co2.05Se4 cathode and activated carbon anode. The device of Ni0.95Co2.05Se4//active carbon (AC) reveals a peak energy density of 37.22 W h kg-1, and the corresponding peak power density reaches 800.90 W kg-1. This work provides a facile and effective way to synthesize transition metal selenides as high-performance supercapacitor electrode materials.

Regulation of Morphology and Electrochemical Properties of Ni0.85Se via Fe Doping for Overall Water Splitting and Supercapacitor

The Fe-doped Ni0.85Se nanosheets array on Ni foam was synthesized successfully through one-step solvothermal method as effective binder-free multifunctional catalysts for hydrogen evolution reaction (HER), oxygen evolution reaction (OER), overall...

Synthesis of a 3D free standing crystalline NiSex matrix for electrochemical energy storage applications

The electrochemical performance for energy storage of three-dimensional (3D) self-supported heterogeneous NiSex cubic-orthorhombic nanocrystals grown by a facile one-step chemical vapour deposition (CVD) approach on Ni foam substrates has been explored. NiSex shows a high specific capacitance of 1333 F g-1 with ultra-high energy (105 W h kg-1) and power (54 kW kg-1) densities. Furthermore, by integrating the as-grown NiSex as the anode and reduced graphene oxide as the cathode, a hybrid supercapacitor (HSC) prototype with a coin cell configuration has been fabricated. The device shows better capacitance (40 F g-1) with high energy (22 W h kg-1) and power (5.8 kW kg-1) densities and robust cycling durability (∼88% capacitance retention after 10 000 repeated cycles). For practical reliability of the as-fabricated HSC, a red LED has been illuminated by connecting it with two charged coin cells. These outstanding performances of the HSC prove to be promising for applications in high energy storage systems.