Engineering Hierarchical Co@N-Doped Carbon Nanotubes/α-Ni(OH)₂ Heterostructures on Carbon Cloth Enabling High-Performance Aqueous Nickel–Zinc Batteries

Abstract

Searching for high-performance Ni-based cathodes plays an important role in developing better aqueous nickel–zinc (Ni–Zn) batteries. For this purpose, herein, we demonstrate the design and synthesis of ultrathin α-Ni­(OH)2 nanosheets branched onto metal–organic frameworks (MOFs)-derived 3D cross-linked N-doped carbon nanotubes encapsulated with tiny Co nanoparticles (denoted as Co@NCNTs/α-Ni­(OH)2), which are directly supported on a flexible carbon cloth (CC). An aqueous Ni–Zn battery employing the hierarchical CC/Co@NCNTs/α-Ni­(OH)2 as the binder-free cathode and a commercial Zn plate as the anode is fabricated, which displays an ultrahigh capacity (316 mAh g–1) and energy density (540.4 Wh kg–1) at 1 A g–1 as well as excellent rate capability (238 mAh g–1 at 10 A g–1) and superior cycling performance (about 84% capacity retention after 2000 cycles at 10 A g–1). The impressive electrochemical performance might benefit from the rich active sites, rapid electron transfer, cushy electrolyte access, rapid ion transport, and robust structural stability. In addition, the quasi-solid-state CC/Co@NCNTs/α-Ni­(OH)2//Zn batteries are also successfully assembled with polymer electrolyte, indicating the great potential for portable and wearable electronics. This work might provide important guidance for constructing carbon-based hybrid materials directly supported on conductive substrates as high-performance electrodes for energy-related devices.

Multifunctional Nickel–Cobalt Phosphates for High-Performance Hydrogen Gas Batteries and Self-Powered Water Splitting

“…However, the pristine Ni­(OH) 2 cathode employed in the Ni–H 2 batteries has disadvantages such as poor electrical conductivity, slow kinetics, and limited specific capacity. − Therefore, it becomes an urgent matter to tackle these issues of the Ni­(OH) 2 cathode for its better deployments. Even though many previous studies have reported that the stability and conductivity of the pristine Ni­(OH) 2 can be optimized via doping with metals such as Co , and Al, , such enhancements are not significant with respect to discharge voltage and specific capacity.…”

Epitaxial Electrocrystallization of Magnesium via Synergy of Magnesiophilic Interface, Lattice Matching, and Electrostatic Confinement

“…This corresponds to the Ni(OH) 2 phase, in good agreement with previous reports. 37,38,40 From the O 1s spectrum (Figure 4c), three peaks at 528.8, 531.2, and 533.5 eV are assigned to metal− oxygen bonds, hydroxyl, and chemisorbed water, respec-tively. 36,37,41 The adsorbed water peak further proves the existence of intercalated water of Ni(OH) 2 @CC, which agrees well with the XRD results.…”

“…The Raman spectra of both Ni­(OH) 2 @CC and Ni­(OH) 2 -M@CC show the lattice modes at 468 and 476 cm –1 (Figure d, green bar), ,− indicating the existence of hydrogen-bonded hydroxyl groups in the two substrates. The O–H stretching modes from lattice OH and intercalated water molecules located in the interlamellar space of Ni­(OH) 2 @CC are observed at about 3550 cm –1 (Figure d, purple bar). − As for the Ni­(OH) 2 -M@CC substrate, there is no detectable peaks at this wavelength, indicating minor intercalated water molecules in the Ni­(OH) 2 -M@CC sample.…”

Core–shell-structured and hydrogen-evolution-suppressing zinc anode for high stability Zn–Ni secondary batteries

“…Generally speaking, the smaller the redox peak difference, the better the reversible degree of the electrode reaction. 41,42 The redox peak differences (Table S2†) for pure ZnO, ZnO@C and ZnO@C/Bi are 0.344 V, 0.322 V, and 0.306 V, respectively. ZnO@C/Bi has the smallest potential difference, indicating that ZnO@C/Bi has better reversibility and lower polarization.…”