Hierarchical FeCo₂S₄@FeNi₂S₄ Core/Shell Nanostructures on Ni Foam for High‐Performance Supercapacitors

Abstract

The design of electrode materials with rational core/shell structures is promising for improving the electrochemical properties of supercapacitors. Hence, hierarchical FeCo 2 S 4 @FeNi 2 S 4 core/shell nanostructures on Ni foam were fabricated by as imple hydrothermalm ethod. Owing to their structure and synergistic effect, they delivera ne xcellent specificc apacitance of 2393Fg À1 at 1Ag À1 and long cycle lifespana sp ositive electrode materials. An asymmetric supercapacitor device with FeCo 2 S 4 @FeNi 2 S 4 as positivee lec-trode and graphene as negative electrode exhibited aspecific capacitanceo f1 33.2 Fg À1 at 1Ag À1 and ah igh energy density of 47.37 Whkg À1 at ap owerd ensityo f8 00 Wkg À1 . Moreover,t he devices howedr emarkable cycling stability with 87.0 %s pecific-capacitance retention after 5000 cycles at 2Ag À1 .T hese results demonstrate that the hierarchical FeCo 2 S 4 @FeNi 2 S 4 core/shell structuresh ave great potentiali n the field of electrochemical energy storage.

Synergistic Tuning of Nickel Cobalt Selenide@Nickel Telluride Core–Shell Heteroarchitectures for Boosting Overall Urea Electrooxidation and Electrochemical Supercapattery

“…Notably, the cell reaches a maximum energy density of 67.7 Wh kg −1 and a power density of 724.8 W kg −1 at 1 A g −1 , while a high energy density of 42.9 Wh kg −1 can still be yielded with a large power density of 7612 W kg −1 at 10 A g −1 . The high energy storage outcomes compare favorably with most previously reported state‐of‐the‐art HASC systems as shown in Figure 8e [ 58–65 ] and Supporting Information Table S3. Besides, the long‐term cycle stability of the assembled cell was assessed by GCD tests at 5 A g −1 for successive 12 000 cycles as shown in Figure 8f.…”

“…The aforementioned findings firmly elucidate that the Ni 6 Co 6 Se@NiTe//AC device has potential electrochemical charge storage performances. Se@NiTe//AC HASC device with those of others reported, [58][59][60][61][62][63][64][65] and f) cycling performance and Coulombic efficiency of Ni6Co6Se@NiTe//AC device at 5 A g −1 .…”

“…a) Cyclic voltammetry (CV) profiles of as‐constructed Ni 6 Co 6 Se@NiTe//AC device at various potential scans, b) CV curves at different sweep rates, c) GCD tests at various current densities, d) capacity value and rate capability as a function of current density, e) comparison of the Ragone plot for the proposed Ni 6 Co 6 Se@NiTe//AC HASC device with those of others reported, [ 58–65 ] and f) cycling performance and Coulombic efficiency of Ni6Co6Se@NiTe//AC device at 5 A g −1 .…”

Recent Progress in Binder‐Free Electrodes Synthesis for Electrochemical Energy Storage Application

“…Apart from various metal‐based skeletons such as Ni foam, [66–69] Cu foam, [70–71] Ti mesh [72] and stainless steel, [73] other substrates have also been employed in the hydrothermal/solvothermal processes to synthesize binder‐free electrodes [74–76] . Among them, carbon fibers are one popular electrode substrate due to their high electrical conductivity, chemical inertness and flexibility [77] .…”

Mixed Cu2Se Hexagonal Nanosheets@Co3Se4 Nanospheres for High‐Performance Asymmetric Supercapacitors

“…Generally, the synthesis method of composite modified electrodes includes multiple steps since the individual components are produced separately. [19][20][21][22] Here, we report a novel strategy to fabricate Cu 2 Se hexagonal nanosheets@Co 3 Se 4 nanospheres through one-step hydrothermal synthesis of mixed CuÀ Co precursor with a subsequent selenization, which not only simplifies the synthesis steps, but also prevents the "dead volume" caused by the binder and improves the utilization of materials by directly growing the electroactive materials on the substrate. By comparing the electrochemical performance of Cu 2 Se@Co 3 Se 4 with its individual components, advantages in rate capability, specific capacitance and cycling stability can be found for Cu 2 Se@Co 3 Se 4 .…”