Electrodeposited thin cobalt branch on cobalt oxides core exhibiting enhanced electrochemical properties

Abstract

Rational design/fabrication of metal oxide/metal composite arrays is critical for construction of advanced energy storage devices. Herein, we assemble ultrathin Co shell on the preformed Co3O4 nanowires core forming porous Co3O4@Co core/shell arrays. In such a composite structure, nanowire arrays possess open spaces for shorter ion diffusion length, while ultrathin metal Co shell has high electronic conductivity for fast electron transfer. As an anode of lithium ion batteries, enhanced Li ion storage properties have been demonstrated for the Co3O4@Co composite nanowire arrays. At a high current density of 3Ag−1, the specific capacity of Co3O4@Co electrode is up to 642mAhg−1, which is much higher than that (440mAhg−1) of the pristine Co3O4 nanowires electrode. These results indicate that conformal deposition of ultrathin metal shell can efficiently enhance the Li ion storage performance of metal oxides.