Synthesis of cobalt ion-based coordination polymer nanowires and their conversion into porous Co_3O_4 nanowires with good lithium storage properties

摘要

Cobalt ion-based coordination polymer nanowires were synthesized by using nitrilotriacetic acid (NA) as a chelating agent by a one-step hydrothermal approach. In the synthesis, cobalt ions were bonded with amino or carboxyl groups of NA to form one-dimension polymer nanowires, which can be confirmed by FTIR and TGA results. Our experimental results show that the morphologies of polymer nanowires greatly depend on the pre-cursor salts, ratios between deionized water and isopropyl alcohol. The probable molecular formula and growth mechanism have been proposed. After heat treatment, the cobalt ion-based coordination polymer nanowires can be converted into porous Co_3O _4 nanowires, which completely preserved the nanowire-like morphology. When used as anodes in lithium-ion batteries, the obtained porous Co _3O_4 nanowires exhibited a high reversible capacity of 810 mA hg~(-1) and stable cyclic retention at 30th cycle. The good electrochemical performance could be attributed to the porous nanostructure of Co_3O_4, which provides pathways for easy accessibility of electrolytes and fast transportation of lithium ions.