High-Performance Battery-Type Supercapacitors Based on Self-Oriented Growth of Nanorods/Nanospheres Composite Assembled on Self-Standing Conductive GO/CNF Frameworks.

MnOx-based materials have limited capacity and poor conductivity over various voltages, hampering their potential for energy storage applications. This work proposes a novel approach to address these challenges. A self-oriented multiple-electronic structure of a 1D-MnO2-nanorod/2D-Mn2O3-nanosphere composite was assembled on 2D-graphene oxide nanosheet/1D-carbon nanofiber (GO/CNF) hybrids. Aided by K+ ions, the MnO2 nanorods were partially converted to Mn2O3 nanospheres, while the GO nanosheets were combined with CNF through hydrogen bonds resulting in a unique double binary 1D-2D mixed morphology of MnO2/Mn2O3-GO/CNF hybrid, having a novel mechanism of multiple Mn ion redox reactions facilitated by the interconnected 3D network. The morphology of the MnO2 nanorods was controlled by regulating the potassium ion content through a rinsing strategy. Interestingly, pure MnO2 nanorods undergo air-annealing to form a mixture of nanorods and nanospheres (MnO2/Mn2O3) with a distinct morphology indicating pseudocapacitive surface redox reactions involving Mn2+, Mn3+, and Mn4+. In the presence of the GO/CNF framework, the charge storage properties of the MnO2/Mn2O3-GO/CNF composite electrode show dominant battery-type behavior because of the unique mesoporous structure with a crumpled morphology that provides relatively large voids and cavities with smaller diffusion paths to facilitate the accumulation/intercalation of charges at the inner electroactive sites for the diffusion-controlled process. The corresponding specific capacity of 800 C g-1 or 222.2 mAh g-1 at 1 A g-1 and remarkable cycling stability (95%) over 5000 cycles at 3 A g-1 were considerably higher than those of the reported electrodes of similar materials. Moreover, a hybrid supercapacitor device is assembled using MnO2/Mn2O3-GO/CNF as the positive electrode and activated carbon as the negative electrode, which exhibits a superior maximum energy density (∼25 Wh kg-1) and maximum power density (∼4.0 kW kg-1). Therefore, the as-synthesized composite highlights the development of highly active low-cost materials for next-generation energy storage applications.

Bimetal-organic frameworks derived redox-type composite materials for high-performance energy storage.

Electrodes and electroactive materials are crucial components in the development of supercapacitors due to their geometric properties. In this study, bimetal-organic frameworks (Bi-MOFs, ZIF-8@ZIF-67) were utilized as electrode materials for a high-performance hybrid supercapacitor (HSC) by designing a novel synthesis of metallic carbonate hydroxide/oxides. In particular, the Bi-MOFs function as a sacrificial precursor in the synthesis of hollow NiMn(CO3)0.5·0·.11H2O/ZnO@Co3O4 CNCs (NM-CH/ZnO@Co3O4 CNCs) cubic composite materials by a straightforward low-temperature treatment. The NM-CH/ZnO@Co3O4 CNCs exhibited exceptional electrochemical performance with high specific capacity of 196.3 ± 0.08 mAh/g, specific capacitance of 1179 ± 0.10 F g-1 at 0.5 A g-1, and outstanding cycling stability of 98% after 25,000 cycles compared to the other electrode materials. The porous and hollow structure, along with a large surface area, contributed to the enhanced electrochemical properties of the composite material. An HSC was constructed using NM-CH/ZnO@Co3O4 CNCs as the cathode and activated porous carbon (APC) as the anode, resulting in a device with a specific energy of 33 ± 0.12 Wh kg-1 and a power density of 19354 ± 0.07 W kg-1. The use of Bi-MOF electrodes presents new avenues for the development of high-performance energy storage materials, with the potential for industrial energy storage application demonstrated though the successful powering of portable lightbulbs.

Strategic Way of Synthesizing Heteroatom-Doped Carbon Nano-onions Using Waste Chicken Fat Oil for Energy Storage Devices.

An easy way of synthesizing low-cost carbon nanomaterials without the need for high-temperature processing approach is critical for energy storage applications because the demand has increased for affordable, long-term, and environmentally friendly synthesized carbon-based materials. Herein, we synthesized multilayered graphitic carbon nano-onions (CNOs) using an oil-wick flame pyrolysis approach, employing biowaste (chicken fat) oil as a cost-effective precursor. The prepared CNOs can provide enhanced ion movement and less resistance for electron transport by interconnecting CNO particles with one another. Furthermore, heteroatom (S,N)-doped CNOs (h-CNOs) were synthesized to optimize the hydrophilic and conductive properties of carbon materials, which eventually exalted the capacitive charge transfer kinetics. The h-CNOs demonstrated superior, highest specific capacitance of 261 F/g, while the undoped CNOs showed a capacitance of 180.6 F/g at a current density of 1 A/g. In addition to capacitance, the h-CNOs also demonstrated a rate capability of 69% and a good cycling stability of 97.5% under high current densities. An asymmetric supercapacitor was fabricated using the h-CNOs as the negative and MnCo2S4 (MCS) as the positive electrode. The device showed high energy and power performance of 32.8 Wh/kg and 7350 W/kg, respectively, with a capacitance retention of 97% over 5000 cycles. Considering the facile strategic way to produce novel carbonaceous materials derived from biowaste oil (chicken fat oil), this could be considered a potential advantage for commercial energy storage devices and may open the door to producing inexpensive, industrially revolutionizing energy storage devices.

Two-Dimensional Core-Shell Structure of Cobalt-Doped@MnO2 Nanosheets Grown on Nickel Foam as a Binder-Free Battery-Type Electrode for Supercapacitor Application.

Herein, we present an interfacial engineering strategy to construct an efficient hydrothermal approach by in situ growing cobalt-doped@MnO2 nanocomposite on highly conductive nickel foam (Ni foam) for supercapacitors (SCs). The remarkably high specific surface area of Co dopant provides a larger contacting area for MnO2. In the meantime, the excellent retentions of the hierarchical phase-based pore architecture of the cobalt-doped surface could beneficially condense the electron transportation pathways. In addition, the nickel foam (Ni foam) nanosheets provide charge-transport channels that lead to the outstanding improved electrochemical activities of cobalt-doped@MnO2. The unique cobalt-doped@MnO2 nanocomposite electrode facilitates stable electrochemical architecture, multi-active electrochemical sites, and rapid electro-transports channels; which act as a key factor in enhancing the specific capacitances, stability, and rate capacities. As a result, the cobalt-doped@MnO2 nanocomposite electrode delivered superior electrochemical activities with a specific capacitance of 337.8 F g-1 at 0.5 A g-1; this is greater than pristine MnO2 (277.9 F g-1). The results demonstrate a worthy approach for the designing of high-performance SCs by the grouping of the nanostructured dopant material and metal oxides.

Self-Supported Co3O4@Mo-Co3O4 Needle-like Nanosheet Heterostructured Architectures of Battery-Type Electrodes for High-Performance Asymmetric Supercapacitors.

Herein, this report uses Co3O4 nanoneedles to decorate Mo-Co3O4 nanosheets over Ni foam, which were fabricated by the hydrothermal route, in order to create a supercapacitor material which is compared with its counterparts. The surface morphology of the developed material was investigated through scanning electron microscopy and the structural properties were evaluated using XRD. The charging storage activities of the electrode materials were evaluated mainly by cyclic voltammetry and galvanostatic charge-discharge investigations. In comparison to binary metal oxides, the specific capacities for the composite Co3O4@Mo-Co3O4 nanosheets and Co3O4 nano-needles were calculated to be 814, and 615 C g-1 at a current density of 1 A g-1, respectively. The electrode of the composite Co3O4@Mo-Co3O4 nanosheets displayed superior stability during 4000 cycles, with a capacity of around 90%. The asymmetric Co3O4@Mo-Co3O4//AC device achieved a maximum specific energy of 51.35 Wh Kg-1 and power density of 790 W kg-1. The Co3O4@Mo-Co3O4//AC device capacity decreased by only 12.1% after 4000 long GCD cycles, which is considerably higher than that of similar electrodes. All these results reveal that the Co3O4@Mo-Co3O4 nanocomposite is a very promising electrode material and a stabled supercapacitor.

Facile synthesis of efficient construction of tungsten disulfide/iron cobaltite nanocomposite grown on nickel foam as a battery-type energy material for electrochemical supercapacitors with superior performance.

In this research literature, a tungsten disulfide/iron cobaltite (WS2/FeCo2O4) interwoven construction array was prepared by a simplistic hydrothermal approach on Ni foam as an integrative electrode for supercapacitors (SCs). For characterization of the wearing of WS2 nanostructure on FeCo2O4 nanosheets (WS2/FeCo2O4) by the Scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The WS2/FeCo2O4 nanosheets supply a larger surface region and sufficient space to allow for volume changes. Moreover, considerable features of wellbeing conductivity from the Ni foam conductor and the synergistic procedures between WS2 and FeCo2O4, the integrated WS2/FeCo2O4 composite achieved prominent SCs storage performances with a higher specific capacity of 1122C g-1 (2492.9F g-1) at 1 A g-1 and notable capacity retention of 98.1% at 3 A g-1 after 5000 long cycles and retained higher rate capacity of 951.9 C g-1 at 15 A g-1. For practical application, an asymmetric supercapacitors type WS2/FeCo2O4//active carbon (WS2/FeCo2O4//AC) device was successfully prepared. The WS2/FeCo2O4//AC device displays a higher specific capacity of 110C g-1 and energy density of 85.68 W h kg-1 at power density at 897.65 W kg-1, as well as the superior initial capacitance of 98.7% with cyclic stabilities after 4000 long cycles. Thus, these results indicated the great potential of the constructed WS2/FeCo2O4//AC in the scenario electrochemical properties due to their outstanding energy storage activities.