Cobalt (Co)-doped MOF-5s (Co-MOF-5s) were first synthesized by a secondary growth method, followed by a heat treatment to yield Co-doped ZnO coated with carbon (CZO@C). Compared with carbon-coated ZnO (ZnO@C), the doping of Co increased the graphitization degree of the carbon on the surface of CZO@C nanoparticles and enhanced the conductivity of the material. The electrochemical properties of the materials were characterized by galvanostatic discharge/charge tests. It was found that the as-synthesized CZO@C composites enabled a reversible capacity of 725 mA h g(-1) up to the 50th cycle at a current density of 100 mA g(-1), which was higher than that of ZnO@C composites (335 mA h g(-1)).
Keywords: anode material; cobalt doping; lithium-ion batteries; metal−organic frameworks; zinc oxide.