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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]

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]

Abstract: Rational construction of electrode materials with exclusive structures and compositions are highly attractive for improving the electrochemical properties of supercapacitors (SCs). In the present study, we demonstrate the construction of unique core–shell Ni−Mn−Co−S@Co(OH)2 nanoarrays on nickel foam (denoted as NMCS@COH/NF) as an attractive battery‐type electrode material for SCs through the hydrothermal and electrodeposition strategies, in which the Ni−Mn−Co−S nanowires are well wrapped in the Co(OH)2 shells. Benefiting from the attractive structural properties, the NMCS@COH/NF electrode exhibits considerable electrochemical properties in the aspects of reasonable rate performance (80.3 % up to 24 A g−1), long‐term cyclability (retention rate of 93.3 % undergoing 10 000 cycles), and exceptional capacity (284.85 mAh g−1 at 2 A g−1). Subsequently, the NMCS@COH electrode is assembled into a hybrid supercapacitor, which delivers a good energy density of 51.1 Wh kg−1 at 751.47 W kg−1 and a maximum power density of 18411.76 W kg−1 at 31.3 Wh kg−1. This work provides a straightforward route to rational construction of the electrode materials with promising structural and electrochemical properties for SC applications. [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]