Novel self-supporting multilevel-3D porous NiO nanowires with metal-organic gel coating via “like dissolves like” to trigger high-performance binder-free lithium-ion batteries

In this work, we put forward a concept of novel self-supporting multilevel-3D porous NiO nanowires and successfully synthesize them to be used as binder-free electrode for lithium-ion batteries (LIBs). According to the “like dissolves like” rule, Zr-based metal-organic gel (Zr-MOG) with the same organic ligand of the precursor of NiO is in situ coated on the surface of novel multilevel-3D porous nanowires, which not only effectively stabilizes the multilevel-3D porous network structure, but also adheres the electrode material to the surface of the Cu foil effectively and prevents electrode pulverization or shedding due to its own viscosity without adding binder (PVDF) in the process of fabricating electrode. Contact angle analysis illustrates Zr-MOG possesses potential to provide cementation power. Through theoretical simulation, the binding energy of NiO@Zr-MOG is lower than NiO, demonstrating the superiority to occur the redox reaction. The novel self-supporting multilevel-3D porous NiO nanowires coated by Zr-MOG possess superior electrochemical performance of LIBs (the specific capacity reached 1816.3 mAh g−1 at the current density of 100 mA g−1, remained at 1318.7 mAh g−1 after 150 cycles). This work will provide a new perspective for the fabrication of high-performance binder-free LIB electrodes.