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

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 alpha-Ni(OH)(2) nanosheets branched onto metal-organic frameworks (MOFs)-derived 3D cross-linked N-doped carbon nanotubes encapsulated with tiny Co nano-particles (denoted as Co@NCNTs/alpha-Ni(OH)(2)), which are directly supported on a flexible carbon cloth (CC). An aqueous Ni-Zn battery employing the hierarchical CC/Co@NCNTs/alpha-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/alpha-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.

Automated summary

The study demonstrates the design and synthesis of a hierarchical cathode structure with ultrathin alpha-Ni(OH)(2) nanosheets branched onto 3D cross-linked N-doped carbon nanotubes encapsulated with Co nano-particles. The resulting battery exhibits impressive capacity, energy density, rate capability, and cycling performance, which can be attributed to factors such as active sites, rapid electron transfer, electrolyte access, ion transport, and structural stability. These findings may guide the development of high-performance energy-related devices using carbon-based hybrid materials supported on conductive substrates.