Hollow Biphase Cobalt Nickel Perselenide Spheres Derived from Metal Glycerol Alkoxides for High-Performance Hybrid Supercapacitors

Exploring the potential of CuCoFeTe@CuCoTe yolk-shelled microrods in supercapacitor applications

Driven by their excellent conductivity and redox properties, metal tellurides (MTes) are increasingly capturing the spotlight across various fields. These properties position MTes as favorable materials for next-generation electrochemical devices. Herein, we introduce a novel, self-sustained approach to creating a yolk-shelled electrode material. Our process begins with a metal-organic framework, specifically a CoFe-layered double hydroxide-zeolitic imidazolate framework67 (ZIF67) yolk-shelled structure (CFLDH-ZIF67). This structure is synthesized in a single step and transformed into CuCoLDH nanocages. The resulting CuCoFeLDH-CuCoLDH yolk-shelled microrods (CCFLDH-CCLDHYSMRs) are formed through an ion-exchange reaction. These are then converted into CuCoFeTe-CuCoTe yolk-shelled microrods (CCFT-CCTYSMRs) by a tellurization reaction. Benefiting from their structural and compositional advantages, the CCFT-CCTYSMR electrode demonstrates superior performance. It exhibits a fabulous capacity of 1512 C g-1 and maintains an impressive 84.45% capacity retention at 45 A g-1. Additionally, it shows a remarkable capacity retention of 91.86% after 10 000 cycles. A significant achievement of this research is the development of an activated carbon (AC)||CCFT-CCTYSMR hybrid supercapacitor. This supercapacitor achieves a good energy density (Eden) of 63.46 W h kg-1 at a power density (Pden) of 803.80 W kg-1 and retains 88.95% of its capacity after 10 000 cycles. These results highlight the potential of telluride-based materials in advanced energy storage applications, marking a step forward in the development of high-energy, long-life hybrid supercapacitors.

Morphological control and performance engineering of Co-based materials for supercapacitors

As one of the most promising energy storage devices, supercapacitors exhibit a higher power density than batteries. However, its low energy density usually requires high-performance electrode materials. Although the RuO2 material shows desirable properties, its high cost and toxicity significantly limit its application in supercapacitors. Recent developments demonstrated that Co-based materials have emerged as a promising alternative to RuO2 for supercapacitors due to their low cost, favorable redox reversibility and environmental friendliness. In this paper, the morphological control and performance engineering of Co-based materials are systematically reviewed. Firstly, the principle of supercapacitors is briefly introduced, and the characteristics and advantages of pseudocapacitors are emphasized. The special forms of cobalt-based materials are introduced, including 1D, 2D and 3D nanomaterials. After that, the ways to enhance the properties of cobalt-based materials are discussed, including adding conductive materials, constructing heterostructures and doping heteroatoms. Particularly, the influence of morphological control and modification methods on the electrochemical performances of materials is highlighted. Finally, the application prospect and development direction of Co-based materials are proposed.

Coaxial nickel cobalt selenide/nitrogen-doped carbon nanotube array as a three-dimensional self-supported electrode for electrochemical energy storage

Herein, we propose a one-step urea pyrolysis method for preparing a nitrogen-doped carbon nanotube array grown on carbon fiber paper, which is demonstrated as a three-dimensional scaffold for constructing a nickel cobalt selenide-based coaxial array structure. Thanks to the large surface area, interconnected porous structure, high mass loading, as well as fast electron/ion transport pathway of the coaxial array structure, the nickel cobalt selenide/nitrogen-doped carbon nanotube electrode exhibits over 7 times higher areal capacity than that directly grown on carbon fiber paper, and better rate capability. The cell assembled by a nickel cobalt selenide/nitrogen-doped carbon nanotube positive electrode and an iron oxyhydroxide/nitrogen-doped carbon nanotube negative electrode delivers a volumetric capacity of up to 22.5 C cm-3 (6.2 mA h cm-3) at 4 mA cm-2 and retains around 86% of the initial capacity even after 10 000 cycles at 10 mA cm-2. A volumetric energy density of up to 4.9 mW h cm-3 and a maximum power density of 208.1 mW cm-3 are achieved, and is comparable to, if not better than, those of similar energy storage devices reported previously.

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

The litchi-like Ni–Co selenide constructed Ni0.95Co2.05Se4//AC hybrid supercapacitor achieves an energy density of 37.22 W h kg−1 and a power density of 800.90 W kg−1. The ASC device can retain 95.21% of the original capacity after 4000 cycles.

The synergistic effect of carbon nanotubes and graphitic carbon nitride on the enhanced supercapacitor performance of cobalt diselenide-based composites

Carbon nanotubes and g-C₃N₄ synergistically optimize the electrical conductivity and spatial structure of CoSe₂, thus improving the performance of supercapacitors.