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Design and fabrication of impressive and novel electrode materials for energy storage devices, especially supercapacitors, are of great importance. Herein, bimetallic CoSe2/FeSe2 hollow nanocuboid nanostructures derived from Co/Fe-Prussian Blue analogues (denoted as CoSe2/FeSe2 HNCs) are successfully designed and fabricated as a remarkable positive electrode material for high-performance supercapacitors. The bimetallic CoSe2/FeSe2 HNC nanostructures can have increased active sites and short electron-ion diffusion pathways. Bimetallic CoSe2/FeSe2 HNCs@NiF as a positive electrode showed efficient supercapacitive properties with a great specific capacity of 332.75 mA h g−1 (1197.90 C g−1) at 1 A g−1, retaining 80.61% of its initial capacity at 20 A g−1, considerable longevity (91.47% of its initial capacity after 10 000 cycles) and an excellent coulombic efficiency of 98.49%. Also, the designed and fabricated CoSe2/FeSe2 HNCs@NiF‖‖AC@NiF hybrid supercapacitor device using bimetallic CoSe2/FeSe2 HNCs@NiF (positive electrode) and activated carbon@NiF (AC, negative electrode) exhibited an efficient energy density of 63.62 W h kg−1 and a superior durability of 91.14% after 10 000 cycles. [ABSTRACT FROM AUTHOR]

Metal–organic framework (MOF) derived nanoarchitectures have special features, such as high surface area (SA), abundant active sites, exclusive porous networks, and remarkable supercapacitive performance when compared to traditional nanoarchitectures. Herein, we propose a viable strategy for the synthesis of hollow manganese nickel selenide spheres comprising nanosheets supported on the nickel foam (denoted as MNSe@NF) from the MOF. The MNSe nanostructures can demonstrate enriched active sites, and shorten the ion-electron diffusion pathways. When the MNSe@NF electrode is used as a cathode electrode for a hybrid supercapacitor, the electrode reflected impressive supercapacitive properties with a high capacity of 325.6 mA h g−1 (1172.16 C g−1) at 2 A g−1, an exceptional rate performance of 86.6% at 60 A g−1, and remarkable longevity (3.2% capacity decline after 15 000 cycles). Also, the assembled MNSe@NF∥AC@NF hybrid supercapacitors employing activated carbon on the nickel foam (AC@NF, anode electrode) and MNSe@NF (cathode electrode) revealed an impressive energy density of 66.1 W h kg−1 at 858.45 W kg−1 and an excellent durability of 94.1% after 15 000 cycles. [ABSTRACT FROM AUTHOR]

Porous structures have attracted considerable attention as promising electrode designs for supercapacitor applications. Herein, we introduce a procedure towards the construction of nanoporous CuCoNi–P nanotube arrays (CCNP-NAs) by a metal–organic framework and hierarchical CoFe2Se4 nanosheet arrays (CFS-NAs) through a hydrothermal strategy, followed by selenization for the flexible asymmetric device. Due to the unique design of the electrode materials, the CCNP-NA and CFS-NA electrodes show exceptional specific capacities of ∼406.73 and 248.2 mA h g−1 at 2 A g−1, reasonable rate capabilities of 84.2 and 71.2% at 50 A g−1, and remarkable durability of 98.9% and 95.1%, respectively. Remarkably, an advanced flexible device was constructed using the CCNP-NA positive electrode and CFS-NA negative electrode. Our flexible device demonstrates tremendous energy density (∼153.5 W h kg−1 at 852.8 W kg−1), super-high durability of 96.2%, and considerable flexibility under bending conditions. This work proposes insight into the rational construction of porous nanostructures for next-generation electronic devices. [ABSTRACT FROM AUTHOR]

Owing to the increased requirement for efficient energy storage systems (ESs), investigating favorable electrodes with porous nanoarchitecture for supercapacitors (SCs) is vital. Nonetheless, the development of these kinds of electrodes to obtain high energy density remains a difficult task. Low specific capacitances of positive (cathode) and negative (anode) electrode materials are a serious obstacle that limits the performance of asymmetric SCs (ASCs). Herein, we proposed the preparation of yolk–shell Cu–Co–P hollow nanospheres (Y-CCP HN) as a positive electrode using a metal–organic framework (MOF) and CuFeS2 nanosheet (CFS NS) arrays as a negative electrode via a low-cost and simple hydrothermal route for ASCs. The Y-CCP HN and CFS NS electrodes exhibited significant specific capacitances (∼2043.3 F g−1 (340.55 mA h g−1) and 654.3 F g−1 (218.1 mA h g−1), respectively), considerable rate performances (∼77.55% and 63.2%, respectively, even at 24 A g−1), and exceptional durability (96.7% and 95.3% after 8000 cycles, respectively). Most notably, the Y-CCP HN//CFS device delivers a wonderful energy density of 158.4 W h kg−1 at a power density of 900.3 W kg−1, a notable specific capacitance of 352.1 F g−1 (176.05 mA h g−1), and excellent cyclability (96.1% after 8000 cycles). This exploration demonstrates a good strategy for the construction of other metal phosphides and sulfides with porous nature, emphasizing considerable prospects for next-generation ESs. [ABSTRACT FROM AUTHOR]

Herein, we proposed a desirable strategy for the synthesis of graphene-wrapped NiCo2Se4 microspheres (positive electrode) and petal-like iron disulfide (FeS2) (negative electrode) on nickel foam substrates. The positive electrode represents a substantial specific capacitance of 2112.30 F g−1 and excellent durability (6.8% loss after 5000 cycles). Furthermore, the negative electrode reflects good electrochemical performance with a specific capacitance of 321.30 F g−1 and a satisfactory rate capability of 47% capacitance retention. Considering the notable properties of the electrodes, a flexible asymmetric all-solid-state device based on graphene-wrapped NiCo2Se4 microspheres (positive electrode) and petal-like iron disulfide (negative electrode) was assembled. Our flexible device exhibits the high specific capacitance of 221.30 F g−1, the significant energy density of 78.68 W h kg−1 and excellent flexibility. [ABSTRACT FROM AUTHOR]

The rational construction of advanced electrode materials with notable performances plays an essential role in the design of energy storage systems with excellent energy density and power density. In this study, for the first time, we offer a facile electrodeposition method for the synthesis of CoGa2O4 (CGO) as an advanced positive (cathode) electrode material supported on a nickel foam substrate to be used in an asymmetric supercapacitor (ASC). The CoGa2O4 (CGO)/nickel foam electrode created an efficacious and fast passageway for ion and electron transport in electrochemical process; for this reason, this electrode illustrated good electrochemical performance including excellent specific capacitance of 1379.16 F g−1 with a remarkable rate performance of 67.2% and excellent durability. Moreover, a pseudocapacitive negative electrode material of ZnFe2O4 (ZFO) was successfully deposited on a nickel foam substrate by a straightforward strategy. The as-constructed ZnFe2O4 (ZFO)/nickel foam electrode revealed a good specific capacitance of 300.5 F g−1 at 1 A g−1, satisfactory rate performance of 55.40% even at 50 A g−1 and significant durability after 6000 cycles. Due to the excellent electrochemical properties of the as-constructed pseudocapacitive electrodes, an asymmetric supercapacitor (ASC) was fabricated using CoGa2O4 (CGO)/nickel foam as an advanced positive (cathode) electrode and ZnFe2O4 (ZFO)/nickel foam as a negative (anode) electrode. The CoGa2O4 (CGO)/nickel foam//ZnFe2O4 (ZFO)/nickel foam device exhibited remarkable performance with good specific capacitance of 232.2 F g−1, excellent rate capability of 64% even at 50 A g−1, outstanding durability even after 6000 cycles and high energy density of 82.56 W h kg−1. Finally, the CoGa2O4 (CGO)/nickel foam//ZnFe2O4 (ZFO)/nickel foam device was employed to light up a blue light-emitting diode (LED), illustrating its significant potential as an advanced ASC device for the modern generation of electronic devices. [ABSTRACT FROM AUTHOR]

In this work, we investigate the application of Ni-Al LDH-rGO composite directly synthesized on nickel foam by a low cost and facile CV electrodeposition method as a new electrode for all-solid-state flexible supercapacitors. Due to the synergistic effects between the Ni-Al LDH and the graphene sheets, directly grown on the surface of Ni foam, the as prepared electrodes exhibit an ultrahigh specific capacitance of 2693.25 F g −1  at a current density of 2 A g −1 . When these electrodes are used in asymmetric (Ni-Al LDH-rGO//Fe 2 O 3 -rGO) and symmetric (Ni-Al LDH-rGO//Ni-Al LDH-rGO) all-solid-stat supercapacitors, the as-prepared devices show excellent flexibility with a maximum specific capacitance and energy density of 214.4 F g −1 and 76.23 Wh Kg −1 for asymmetric device, and 412.30 F g −1 and 36.65 Wh Kg −1 for symmetric device. [ABSTRACT FROM AUTHOR]

Designing advanced electrode materials with porous structures and prominent electrochemical activity could be a novel approach toward improving the energy density of supercapacitors (SCs). Herein, the construction of hollow MnCo 2 S 4 nanowires decorated with NiFeLDH nanosheets (MCS@NFLDH) as a promising binder-free electrode for SCs using the effective sulfurization and hydrothermal procedures is introduced. Furthermore, the MCS@NFLDH electrode texture wrapped by graphene (rGO) sheets would take the benefit of superior structural properties and amazing electrochemical performances. The MCS@NFLDH@rGO electrode reflects a considerable capacity of ≈327.3 mAh/g, a substantial rate capability of 73.2% at 20 A/g, and superior robustness. With the well-constructed nanostructures, a corresponding asymmetric supercapacitor (ASC) device based on MCS@NFLDH@rGO (positive electrode) and active carbon (AC) (negative electrode) was assembled and tested. Most importantly, the device reflects a satisfactory energy density of ≈47.98 Wh/kg and an exceptional robustness. Accordingly, this work opens up the opportunities for the well-design of binder-free electrodes for utilization in SCs and other energy storage devices (ESDs). Hierarchical MnCo 2 S 4 nanowires/NiFeLDH nanosheets/graphene nanostructures are constructed by a hydrothermal strategy for asymmetric supercapacitor. Image 1 [ABSTRACT FROM AUTHOR]

Owing to the high demands for fascinating energy storage devices, exploring cost-effective electrodes with exclusive architectures for supercapacitors is crucial; however, the advent of such electrodes to achieve the industrial necessities remains a challenging task. Herein the design and characterization of roselike nanoporous ZnGa2S4 hollow spheres (RN-ZGSHS) are described. This structure with the surface area of 71.7 m2 g−1 can provide a capacity of 358.4 mAh g−1 at 2 A g−1 and capacity of 260.2 mAh g−1 at 50 A g−1, as well as significant robustness of 98.4%. To achieve higher energy density in the asymmetric energy storage device, a yolk-shell nanoporous iron phosphide hollow spheres (YS–FePHS) as a negative electrode is also designed. The designed anode electrode with a quasi-rectangular-like character can deliver a capacity of 117.5 mAh g−1 at 1 A g−1 and maintains a high capacity of 65.8 mAh g−1 at 25 A g−1, with satisfactory robustness of 89.9%. Ultimately, the constructed asymmetric device (RN-ZGSHS//YS-FePHS) depicts the ED of 72.78 W h kg−1 at a power density (PD) of 800 W kg−1, while keeps a high energy density of 49.13 W h kg−1 at a power density of 64148.53 W kg−1. Image 1 • Rose-like nanoporous ZnGa 2 S 4 hollow spheres are synthesized as cathode electrode. • Yolk-shell nanoporous iron phosphide hollow spheres are prepared as anode electrode. • Cathode and anode electrodes exhibit high electrochemical performance. • An asymmetric supercapacitor is assembled based on cathode and anode electrodes. • The asymmetric supercapacitor illustrates excellent energy density. [ABSTRACT FROM AUTHOR]