Coral-Inspired Hierarchical Structure Promotes a Win–Win on Mass Loading and Rate Capability: A Nickel–Cobalt–Zinc–Sulfide@Nickel–Cobalt Layered Double Hydroxide Electrode for a High-Performance Hybrid Supercapacitor

Abstract

A hierarchical structure, defined as structural features occurring on different levels of scale, is widely used in the rational design of composite electrodes for its superiorities in abundant electrochemical active sites and functional differentiation for various components. Herein, we in situ prepare a nickel–cobalt layered double hydroxide (NiCo-LDH) nanosheet network on ultrathin nickel–cobalt–zinc–sulfide (NiCoZnS x ) microplate arrays to construct a special, coral-inspired hierarchical structure. In this structure, NiCoZnS x microplate arrays not only provide plenty of rooms for nanosheet growth but also improve the ion diffusion, charge transfer, and structural stability of the composite electrode. The NiCo-LDH nanosheet network paved through the microplate surface offers a high specific surface area and capacitance. The composite electrode delivers a high specific capacitance of 8.1 F cm–2 (1928 F g–1) at a loading mass of 4.2 mg cm–2, outstanding rate capability (63% capacitance retention, 50 mA cm–2), and cycling stability (80% capacitance retention, 10 000 cycles). Furthermore, the hybrid asymmetric supercapacitor assembled by the composite electrode and active carbon exhibits a maximal power density of 80.3 mW cm–2 at an energy density of 270 μWh cm–2 with good rate capability and cycling stability. This work reveals the significance and practical potential of rational design in the electrode’s hierarchical structure for a high-performance supercapacitor.

Efficient improvement in the electrochemical performance of petal-like lamellar NiMn–LDHs with affluent oxygen vacancies derived from Mn MOF-74

“…It is worth mentioning that the characteristic structure of O–LDH features a rougher surface, providing more surfaced active sites and contributing to electrolyte diffusion. 46 a ,48 In addition, partial hollow structures resulting from the corrosion effect are conducive to the quick transmission of electrolyte ions and may immensely improve the electrical conductivity compared to the original NiMn–LDH 3. 49 As presented in the EDX elemental analysis results in Fig.…”

“…The lamellar formed by the pore and channel interaction became more numerous and complex due to the further deepening for the surface roughness of the material. 48,51,53,56 Therefore, the electrochemical performance can be further improved by increasing the specific surface area. The capacitance retention of the three electrode materials at different current densities is shown in Fig.…”

Exceeding 50 000 Cycle Durability of Layered Hydroxide‐Based Hybrid Supercapacitor Through Scandium Doping‐Induced Superlong Activation Process

“…When b equals to 1, the reaction shows a capacitive and surface‐controlled electrochemical behavior; when b equals to 0.5, the reaction shows a battery‐type and diffusion‐controlled electrochemical behavior. [ 16 ] The kinetic characteristics of the redox reactions could be obtained by calculating slope of the fitting line of logarithmic peak current and scan rate. As shown in Figure 3c, P An,2 and P Ca,2 show a b value of 0.89 and 0.83 (b2 and b4 in Figure 3c), suggesting a surface‐controlled kinetics, while P An,1 and P Ca,1 with a b value of 0.65 and 0.63 (b1 and b3 in Figure 3c) show a diffusion‐controlled kinetics.…”

Recent advances in Ni-materials/carbon nanocomposites for supercapacitor electrodes

“…The various supercapacitors based on the Ni materials//active carbon electrodes have been employed in electrochemical applications, and the novel results of the reported papers are tabulated in Table 4. 182–219 The utilization of active carbon in supercapacitors highlights its valuable role in improving energy storage capabilities and supporting advancements in various fields where efficient power delivery and rapid energy transfer are essential. Ni(OH) 2 /ZIF-67-derived CoS core/carbon cloth (Ni(OH) 2 /CoS/CC) was used in the supercapacitor of Ni(OH) 2 /CoS/CC (cathode)//AC (anode) that revealed a remarkable energy density as well as its excellent electro-catalytic activity towards methanol oxidation.…”

“…208 In the production of NiCo-LDH (layered double hydroxide) nanosheets on an ultrathin NiCoZnS x (sulfide) microplate were prepared and exhibited a high specific capacitance of 1928 F g À1 and outstanding rate capability as well as a high energy density and good cycling stability of its supercapacitor with AC electrode. 209 NiCoP (phosphide) composites with carbon cloth (NiCoP@CC) and Co-based ZIF-67 (Co-ZIF-67) were prepared and the NiCoP@CC electrode showed a remarkable specific capacity of 1149.2 C g À1 and good traits. The supercapacitor of the NiCoP@CC cathode and AC as the anode delivered a high specific energy.…”