Cobalt Oxide Nanorod Anode for Lithium Ion Battery

Nanomaterials with one-dimensional (1-D) structure have been extensively studied as electrode materials for such functional electrochemical devices as sensors, supercapacitors, and rechargeable batteries. In particular, the nanorod electrode is considered as one of the most promising options for thin film lithium batteries because of its enhanced structural stability during lithiation/delithiation cycling and rate capability.

Template–assisted methods using anodic aluminum oxide or polycarbonate have been usually used for the synthesis of nanorod electrodes. However, the use of template typically makes the preparation procedure complex and resulted often in unintended aggregation of nanorods after the template removal.

This work focuses on the preparation of the cobalt-based nanorod arrays for the anode in lithium ion batteries by a template-free electrochemical synthesis of cobalt nanorod and its subsequent oxidation. Cobalt electro-deposit showed different growth habit depending on the deposition parameters of temperature, current density and bath chemistry, and well-defined 1-D nanorod structure was successfully fabricated under their careful control. The following thermal oxidation of the cobalt nanorod led to cobalt/cobalt oxide bilayer composites with little change in its macroscopic structure.

In this presentation, the morphology and structure of the as-prepared pure cobalt nanorod and its oxidized product (i.e., cobalt / cobalt oxide nanorod composite) will be presented. Moreover, the electrochemical properties of nanorod composites will be discussed on the basis of the cyclic voltammograms, galvanostatic charge-discharge curves, and electrochemical impedance spectra. The rate performance and long-term cycling stability of the nanorod composites will be particularly highlighted.

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