Metal-organic-framework derived hollow manganese nickel selenide spheres confined with nanosheets on nickel foam for 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.

Advances in Mn-Based MOFs and Their Derivatives for High-Performance Supercapacitor

As the most widely used metal material in supercapacitors, manganese (Mn)-based materials possess the merits of high theoretical capacitance, stable structure as well as environmental friendliness. However, due to poor conductivity and easy accumulation, the practical capacitance of Mn-based materials is far lower than that of theoretical value. Therefore, accurate structural adjustment and controllable strategies are urgently needed to optimize the electrochemical properties of Mn-based materials. Metal-organic frameworks (MOFs) are porous materials with high specific surface area (SSA), tunable pore size, and controllable structure. These features make them attractive as precursors or scaffold for the synthesis of metal-based materials and composites, which are important for electrochemical energy storage applications. Therefore, a timely and comprehensive review on the classification, design, preparation and application of Mn-based MOFs and their derivatives for supercapacitors has been given in this paper. The recent advancement of Mn-based MOFs and their derivatives applied in supercapacitor electrodes are particularly highlighted. Finally, the challenges faced by Mn-MOFs and their derivatives for supercapacitors are summarized, and strategies to further improve their performance are proposed. The aspiration is that this review will serve as a beneficial compass, guiding the logical creation of Mn-based MOFs and their derivatives in the future.

In situ tellurization strategy for crafting nickel ditelluride/cobalt ditelluride hierarchical nanostructures: A leap forward in hybrid supercapacitor electrode materials

Advancements in renewable energy conversion can be significantly propelled by optimizing the performance of transition-metal-based electrodes. In this study, we introduce an innovative, in situ tellurization strategy to synthesize novel, flower-like hierarchical structures of nickel ditelluride/cobalt ditelluride (NiTe2/CoTe2) on a nickel foam substrate (labeled as NF/FNCT), making them promising candidates for electrodes in hybrid supercapacitors. Initially, we utilized a hydrothermal method to create flower-like NiCo-layered double hydroxide (NiCo-LDH) nanoarrays on nickel foam (NF/FNCLDH). This process was followed by the tellurization of these nanoarrays, which yields the NiTe₂/CoTe₂ nanostructures. The strategic assembly of active materials on a conductive substrate effectively obviates the need for inert, slow-conductive binders, thereby facilitating redox chemistry. Capitalizing on the synergistic effects of the conductive tellurium and hierarchical flower-like nanomorphology, the NF/FNCT showcases expedited electron/ion transport, enhanced efficiency, and exceptional electrochemical performance. The NF/FNCT electrode discloses an impressive capacity of 1388.9 (±3) C/g, superior rate capability (83.45 % capacity retention at 30 A/g), and remarkable cycling durability of 96.67 %. Furthermore, when integrated with activated carbon (AC), the resultant hybrid supercapacitor delivers a desirable energy density of 58.85 Wh kg-1 at a power density of 806.85 W kg-1, demonstrating commendable rate capability and cycling durability. This investigation opens new avenues for the synthesis of materials for hybrid supercapacitors.

Biosynthesis of ternary NiCoFe2O4 nanoflowers: investigating their 3D structure and potential use in gene delivery

Multicomponent nanoparticle systems are known for their varied properties and functions, and have shown potential as gene nanocarriers. This study aims to synthesize and characterize ternary nickel-cobalt-ferrite (NiCoFe2O4) nanoparticles with the potential to serve as gene nanocarriers for cancer/gene therapy. The biogenic nanocarriers were prepared using a simple and eco-friendly method following green chemistry principles. The physicochemical properties of the nanoparticles were analyzed by X-ray diffraction, vibrating sample magnetometer, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller. To evaluate the morphology of the nanoparticles, the field emission scanning electron microscopy with energy dispersive X-Ray spectroscopy, high-resolution transmission electron microscopy imaging, and electron tomography were conducted. Results indicate the nanoparticles have a nanoflower morphology with a mesoporous nature and a cubic spinel structure, where the rod and spherical nanoparticles became rose-like with a specific orientation. These nanoparticles were found to have minimal toxicity in human embryonic kidney 293 (HEK-293 T) cells at concentrations of 1 to 250 µg·mL-1. We also demonstrated that the nanoparticles could be used as gene nanocarriers for delivering genes to HEK-293 T cells using an external magnetic field, with optimal transfection efficiency achieved at an N/P ratio of 2.5. The study suggests that biogenic multicomponent nanocarriers show potential for safe and efficient gene delivery in cancer/gene therapy.

ZIF-67-derived Co/CoSe ultrafine nanocrystal Schottky heterojunction decorated hollow carbon nanospheres as new-type anodes for potassium-ion batteries

Metal-organic frameworks (MOFs) have the advantages of controllable chemical properties, rich pore structures and reaction sites and are expected to be high-performance anode materials for the next generation of potassium-ion batteries (PIBs). However, due to the large radius of potassium ions, the pure MOF crystal structure is prone to collapse during ion insertion and processing, so its electrochemical performance is quite limited. In this work, a hollow carbon sphere-supported MOF-derived Co/CoSe heterojunction anode material for potassium-ion batteries was developed by a hydrothermal method. The anode has high potassium storage capacity (461.9 mA h/g after 200 cycles at 1 A/g), excellent cycling stability and superior rate performance. It is worth noting that the potassium ion storage capacity of the anode material shows a gradual upward trend with the charge-discharge cycle, which is 145.9 mA h/g after 3000 cycles at a current density of 10 A/g. This work demonstrates that MOF-derived CoSe anodes with high capacity and low cost may be promising candidates for the introduction of potassium ion storage.

Fabrication of nanosheet-assembled hollow copper-nickel phosphide spheres embedded in reduced graphene oxide texture for hybrid supercapacitors

Owing to their metalloid characteristics with high electrical conductivity, transition metal phosphides (TMPs) have attracted considerable research attention as prospective cathodes for hybrid supercapacitors. Unfortunately, they usually exhibit low rate performance as well as poor longevity, which does not meet the demands of hybrid supercapacitors. The nanocomposite constructed from reduced graphene oxide (rGO) and TMPs with a highly porous nature can effectively overcome the above-mentioned issues, greatly widening their utilization. In this work, we fabricated nanosheet-assembled hollow copper-nickel phosphide spheres (NH-CNPSs) by the controllable phosphatizing of copper-nickel-ethylene glycol (CN-EG) precursors. Then, porous NH-CNPSs were embedded in rGO texture (NH-CNPS-rGO) to form a unique porous nanoarchitecture. The obtained NH-CNPS-rGO has several advantages benefiting as the cathode electrode, such as (i) the hollow structure as well as porous nanosheets are conducive to fast electrolyte diffusion, (ii) the electrical conductivity of NH-CNPS is further enhanced when coupled with the rGO texture, hence promoting electron transfer in the whole structure, (iii) wrapping NH-CNPSs within the rGO texture endows the nanocomposite with much better structural stability, resulting in longer durability of the electrode, And (iv) the porous structures generated in the nanocomposite provide a perfect space for reducing the mass transfer resistance and accessing the electrolyte, thereby boosting the reaction kinetics. The tests demonstrated that the optimal NH-CNPS-rGO electrode revealed a capacity of up to 1075 C g^-1, a superior rate capacity, and exceptional longevity of 94.7%. Moreover, a hybrid supercapacitor (NH-CNPS-rGO‖AC) equipped with the NH-CNPS-rGO-cathode electrode and activated carbon (AC)-anode electrode represented a satisfactory energy density of 64 W h kg^-1 at 801 W kg^-1 and amazing longevity (91.8% retention after 13 000 cycles), which endorses the promising potential of NH-CNPS-rGO for high-efficiency supercapacitors. This research showcases an appropriate method to engineer hollow TMP-rGO nanocomposites as effective materials for supercapacitors.

H-CoNiSe2/NC dodecahedral hollow structures for high-performance supercapacitors

The synergistic effect between metal ions and increasing the surface area leads to the fabrication of supercapacitor materials with high capacities. It is predicted that transition metal selenide compounds will be ideal electrode materials for supercapacitors. However, the defects of poor conductivity and volume expansion of the compounds are fundamental problems that must be solved. In this work, we successfully synthesized the cobalt-nickel selenide nitrogen-doped carbon (H-CoNiSe₂/NC) hollow polyhedral composite structure using ZIF-67 as a precursor. The CoSe₂ and NiSe₂ nanoparticles embedded in the NC polyhedral framework offer a wealth of active sites for the whole electrode. Moreover, the presence of the NC structure in the proposed composite can simultaneously lead to improved conductivity and reduce the volume effect created during the cycling procedure. The H-CoNiSe₂/NC electrode provides high specific capacity (1131 C/g at 1.0 A/g) and outstanding cyclic stability (90.2% retention after 6000 cycles). In addition, the H-CoNiSe₂/NC//AC hybrid supercapacitor delivers ultrahigh energy density and power density (81.9 Wh/kg at 900 W/kg) and excellent cyclic stability (92.1% of the initial capacitance after 6000 cycles). This study will provide a supercapacitor electrode material with a high specific capacity for energy storage devices.Please confirm the corresponding affiliation for the 'Ali A. Ensafi' author is correctly identified.Error during converting author query response. Please check the eproofing link or feedback pdf for details.

Wet-chemical assisted synthesis of MnSe/ZnO nanostructures as low-resistance robust novel cathode material for advanced hybrid supercapacitors

We proposed a novel MnSe–ZnO-based binary nanocomposite synthesized via a wet-chemical assisted method which deliver high power and energy densities, suppressing previous reports on MnSe and ZnO with decent cycling durability with good rate performance.

A Study on the Effect of Graphene in Enhancing the Electrochemical Properties of SnO2-Fe2O3 Anode Materials

To enhance the conductivity and volume expansion during the charging and discharging of transition metal oxide anode materials, rGO-SnO₂-Fe₂O₃ composite materials with different contents of rGO were prepared by the in situ hydrothermal synthesis method. The SEM morphology revealed a sphere-like fluffy structure, particles of the 0.4%rGO-10%SnO₂-Fe₂O₃ composite were smaller and more compact with a specific surface area of 223.19 m²/g, the first discharge capacity of 1423.75 mAh/g, and the specific capacity could be maintained at 687.60 mAh/g even after 100 cycles. It exhibited a good ratio performance and electrochemical reversibility, smaller charge transfer resistance, and contact resistance, which aided in lithium-ion transport. Its superior electrochemical performance was due to the addition of graphene, which made the spherical particle size distribution more uniform, effectively lowering the volume expansion during the process of charging and discharging and improving the electrochemical cycle stability of the anode materials.