The dodecahedral Nitrogen-doped carbon coated ZnO composite derived from zeolitic inidazolate framework-8 with excellent cycling performance for zinc based rechargeable batteries

A novel Nitrogen-doped carbon coated ZnO(NC@ZnO) composite derived from zeolitic inidazolate framework-8 (ZIF-8) precursor is successfully synthesized through a simple hydrothermal reaction followed by calcination treatment. The as-prepared NC@ZnO composite is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Ni-trogen adsorption-desorption analysis, and its formation mechanism is proposed. When evaluated as anode material for Ni-Zn alkaline secondary batteries, the NC@ZnO composite exhibits outstanding electrochemical performance compared with that of the commercial ZnO, delivering a discharge specific capacity of 531 mAh g(-1) with the capacity retention ratio about 83.5% after 945 cycles. The outstanding electrochemical performance is ascribed to the Nitrogen-doped carbon layer and the unique dodecahedral porous architectures with a larger specific surface area, which can facilitate the electrons transfer and restrain the formation of zinc dendrites during repeated charge-discharge process.