Porous ZnO@C core–shell nanocomposites as high performance electrode materials for rechargeable lithium-ion batteries

A novel porous spherical ZnO@carbon (C) nanocomposite based on zeolitic imidazolate frameworks (ZIFs-8)-directed method was prepared for lithium-ion batteries (LIBs). In this strategy, spherical ZnO nanoparticles were firstly prepared, then 2-methylimidazolate and Zn2+ were added alternately under ultrasound to fabricate ZnO@ZIF-8. Finally, the novel porous spherical ZnO@C nanocomposites were obtained via pyrolyzing the corresponding ZnO@ZIF-8. The novel porous spherical ZnO@C nanocomposites were characterized with different analysis techniques such as scanning electron microscopy, transmission electron microscopy and X-ray powder diffraction. The resulted spherical ZnO@C nanocomposites exhibited a high reversible capacity of 932 mA h g−1 at 0.1 A g−1 after 100 cycles, which is much higher than that of the pure ZnO nanoparticles. The porous structure, high specific surface area and good electrical conductivity eventually contribute to the good performance of the resulted ZnO@C nanocomposites for LIBs should be ascribed to the proous structure and high BET surface area derived from ZIFs, as well as the good electrical conductivity of the amourphous carbon derived from ZIFs.