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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]

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]

Electrode materials with unique nanoarchitecture, great conductivities, and desirable mechanical stabilities are essential for developing nearly all energy storage devices (ESDs). Herein, a low‐cost route for the fabrication of double‐layer CuCo2S4@Ni−Mo−S (CCS@NMS) nanosheet arrays as an advanced binder‐free positive electrode for supercapattery is presented. The CCS@NMS porous nanoarchitecture has the advantages of good ion diffusion and excellent electronic transport. Accordingly, when employed as battery‐type electrode in supercapattery device, the CCS@NMS electrode reflects amazing capacity (Cs) of 446.3 mAh g−1 (3213.6 F g−1) at 1 A g−1 and 375.8 mAh g−1 (2705.85 F g−1) at 18 A g−1, and 98.2 % of the Cs was still maintained at 6 A g−1 after 5000 cycles, which are higher than that of CCS electrode. Most importantly, using the CCS@NMS electrode as the positive electrode and active carbon (AC) as the negative electrode, the device indicates notable Cs of 66.8 mAh g−1 (160.4 F g−1), the considerable specific energy of 50.125 Wh kg−1 at a specific power of 750.04 W kg−1 and outstanding robustness of 96.8 %. [ABSTRACT FROM AUTHOR]

A facile synthetic route has been proposed to prepare cauliflower-like nanostructures of Cr doped Mn 2 O 3 . The synthesis was carried out by constant current cathodic electrodeposition from Mn 2+ nitrate solutions containing minor amounts of dichromate. It was found that the presence of Cr mediates the formation of cathodic MnO 2 which then reacts with the excess Mn 2+ species to form Mn 2 O 3 nanostructures. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Differential Thermal Analysis (DTA) were used to characterize the nanostructures. The storage ability of the obtained nanostructures was investigated by cyclic voltammetry (CV) in 0.5 M Na 2 SO 4 solution. The results indicated that the Cr doped manganese oxide material shows better performance than the non-doped one, and the charge capacity (SC) of doped manganese oxide (218 F/g) was higher than pure manganese oxide (208 F/g). [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]