Conformal construction of polyaniline shell on cobalt oxide nanoflake core for enhanced Li ion storage

Abstract It is of great importance to controllably synthesize non-axial metal oxide/conducting polymers arrays for construction of high-performance electrochemical devices. In this work, we develop a facile electro-polymerization method to conformally coat interwoven polyaniline (PANI) shell on the preformed porous Co3O4 nanoflakes forming non-axial Co3O4/PANI core/shell arrays. Uniform conductive PANI network and high porosity are realized in the non-axial core/shell arrays. As active materials for Li ion storage, the Co3O4/PANI core/shell arrays show superior high-rate performance including lower polarization, higher reactivity and better cycling life, as compared to the unmodified Co3O4 nanoflake arrays. The capacity deterioration of the Co3O4/PANI arrays is restricted to a very lower level with a capacity of 871 mAh g−1 at 0.25 A g−1 after 100 cycles, better than the Co3O4 counterpart (669 mAh g−1 at 0.25 A g−1). This non-axial combination opens up a new door for developing advanced composite arrays for energy storage.