Construction of Cu₇KS₄@Ni_xCo_1–x(OH)₂ Nano-Core–Shell Structures with High Conductivity and Multi-Metal Synergistic Effect for Superior Hybrid Supercapacitors

Abstract

Reasonable design of materials with complex nanostructures and diverse chemical compositions is of great significance in the field of energy storage. Cu7KS4 (CKS) is considered a potential electrode material for supercapacitors due to its superior electrical conductivity. Transition metal hydroxides are widely used as electrode materials for supercapacitors due to their high theoretical specific capacitance (C s); however, single metal species with limited active sites restrict their further applications for energy storage. Herein, through a hydrothermal reaction, CKS nanorods were prepared, and then binary metal hydroxide Ni x Co1–x (OH)2 nanosheets were generated directly on CKS nanorods through a one-step hydrothermal reaction to form a nano-core–shell structure (NCSS). By regulating the mole ratio of nickel nitrate to cobalt nitrate, the resulting Ni0.75Co0.25(OH)2 nanosheets with the best electrochemical activity were prepared and supported on CKS nanorods to form a CKS@N0.75C0.25OH NCSS. The as-prepared CKS@N0.75C0.25OH NCSS has a larger specific surface area, which can provide more active sites, while the abundant metal species composition can generate abundant redox reactions to boost the pseudocapacitance. The prepared CKS@N0.75C0.25OH/NF electrode exhibits outstanding specific capacitance and cycle life. The assembled CKS@N0.75C0.25OH/NF//AC all-solid-state asymmetric supercapacitor achieves a high energy density of 88.7 Wh kg–1 at a power density of 849.9 W kg–1 with superior cycle life. Therefore, the use of polymetallic hydroxides to construct NCSS electrodes has great research significance and broad application prospects.

Unveiling the potential of nanosheet-based NiTe2@MnTe hollow nanospheres in hybrid supercapacitor technology

“…This switch to surface capacitive dominance under higher sweep speeds can be attributed to restricted ion diffusion into the lattice. 65 The GCD patterns of NMT-HS, ranging from 1 to 25 A g −1 , embody nonlinear characteristics associated with faradaic reactions and battery-like behaviors (Fig. 6a).…”

“…This switch to surface capacitive dominance under higher sweep speeds can be attributed to restricted ion diffusion into the lattice. 65…”

Ultrathin Dielectric Triggered Charge Injection Dynamics for High-Performance Metal Organic Framework/MXene Supercapacitors

“…This pattern implies a distinct separation and indicates a dominant diffusion-controlled process within the electrochemical system, attributed to the reversible Faradaic reactions. 41 The GCD curves in Figure 4e exhibit symmetrical charge−discharge curves at different current densities ranging from 1 to 10 A/g, demonstrating high Coulombic efficiency and reversibility. Additionally, the electrochemical dynamic behavior and conductivity of the integrated electrodes were explored by measuring EIS, as illustrated in Figure 4c.…”

Mixed solvent-assisted synthesis of high mass loading amorphous NiCo-MOF as a promising electrode material for supercapacitors

“…1,2 Generally, the energy storage process of supercapacitors is carried out on the surface of electrodes. 3 Therefore, the design and synthesis of electrode materials with novel shapes and large surface area play a crucial role. To date, various electrode materials including hydroxides, 4 sulfides, 5 metal oxides, 6 phosphides, 7 selenides 8 and MOFs 9 have been studied and developed.…”