MOF-derived ZnCo₂O₄@NiCo₂S₄@PPy core–shell nanosheets on Ni foam for high-performance supercapacitors

Abstract

The ZnCo2O4@NiCo2S4@PPy core–shell nanosheets material is prepared by directly growing leaf-like ZnCo2O4 nanosheets derived from the metal-organic framework (MOF) on Ni foam (NiF) via chemical bath deposition and annealing methods and then combining with NiCo2S4 and PPy via electrodeposition methods. The special core–shell structure formed by MOF-derived ZnCo2O4, NiCo2S4 and PPy creates a bi-interface, which could significantly promote the contact between electrode and electrolyte, provide more active sites and accelerate electron/ion transfer. And the combination of these three materials also produces a strong synergistic effect, which could further improve the capacitive performance of the electrode. Therefore, the ZnCo2O4@NiCo2S4@PPy/NiF electrode exhibits the maximum areal capacitance (3.75 F cm−2) and specific capacitance (2507.0 F g−1) at 1 mA cm−2 and 0.5 A g−1, respectively. Moreover, its capacitance retention rate is still 83.2% after 5000 cycles. In addition, a coin-type hybrid supercapacitor is assembled and displays a high energy density of 44.15 Wh kg−1 and good cycling performance.

Tailoring Mo-Doped NiCoP Grown on (Ni,Co)Se2 Nanoarrays for Asymmetric Supercapacitor with Enhanced Electrochemical Performance

“…The rational design of the nanostructure would expand the specific surface area and types of active sites of electrode materials, boosting electrochemical performance. Core–shell structure materials have exhibited fast reaction kinetics, large active area, and enhanced structural stability in numerous works. − Li et al designed the core–shell (Ni,Co)­Se 2 @Ni-CoLDH combining (Ni,Co)­Se 2 having high reactive activities with Ni-CoLDH possessing a high specific surface area, presenting a high capacity of 170 mAh/g (612 C/g) at 2 A/g and a remarkable durability of 89.5% capacity retention after 3000 cycles . On consideration of the diverse synthesis processes of Ni-Co LDH nanoflakes, , the electrodeposition method is uncomplicated and low-cost, which could manage the mass loading and morphology of materials .…”

Electrochemical deposition of ZnCo2O4/NiCo2S4 nanosheet arrays for high-performance supercapacitors

“…9b displays the Ragone plot of the ZCO-20/NCS//AC ASC and comparison with some previous references. 46–53 The maximal energy density of the ZCO-20/NCS//AC ASC is 57.28 W h kg −1 at a power density of 800 W kg −1 , while the minimal energy density of the ASC is 46.50 W h kg −1 at a higher power density of 8.0 kW kg −1 .…”

“…Liu et al 45 synthesized phosphorus-substituted nickel-cobalt sulfides nanosheet arrays on nitrogen-doped carbonic nanofibers by electrochemical deposition, which exhibited a high specific capacitance of 1938 F g −1 at 0.5 A g −1 . Zhu et al 46 synthesized a core-shell structure of ZnCo 2 O 4 @NiCo 2 S 4 @PPy/NiF as a supercapacitor electrode, which exhibited a high capacitance of 2507 F g −1 at 0.5 A g −1 . Though transition-metal oxides and sulfides are competitive materials for supercapacitor electrodes, their performance is usually unsatisfactory under high charge/discharge current densities.…”

Fabrication of Bimetallic Oxides (MCo2O4: M=Cu, Mn) on Ordered Microchannel Electro-Conductive Plate for High-Performance Hybrid Supercapacitors

“…Binary transition metal oxides (BTMOS) are important multifunctional materials composed of two metal elements. Due to their unique structure and properties, they have attracted extensive attention in catalysis, heavy metal ion adsorption, electrocatalyst, sensor, lithium-ion batteries and supercapacitors [5][6][7][8] 4 have attracted extensive attention due to their high specific capacitance, better rate performance and stability electrochemical properties, and are considered to have the most potential electrode material for energy storage, especially supercapacitors [9][10][11][12][13].…”