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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]

The development of durable, beneficial, and highly active non-precious metal-based electrocatalysts for hydrogen generation is a vital concern. This study proposes an effective strategy for the construction of Fe doped CoP nanosheet arrays wrapped by graphene (F0.25CP-G) on nickel foam as an efficient electrocatalyst for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). In this design, the final catalyst possesses a combination of the high conductivity of graphene, great surface porosity, and the intrinsic electrocatalytic activity of the F0.25CP-G which results in high-performance electrocatalytic activity toward the HER and OER. Therefore, the as-synthesized F0.25CP-G catalyst can achieve overpotentials of 66 mV and 230 mV for the HER and OER, respectively, in KOH at 10 mA cm−2. Furthermore, a practical electrolyzer (F0.25CP-G‖‖F0.25CP-G) exhibits a current density of 10 mA cm−2 at 1.60 V along with good durability for 24 h. [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]