Interconnected Co^sub 3^O^sub 4^@CoNiO^sub 2^@PPy nanorod and nanosheet composite grown on nickel foam as binder-free electrodes for Li-ion batteries

Transition metal oxides are considered as promising anodes material with enormous potential for Li-ion batteries, and much effort are devoted to resolving the high resistance and inferior cycling behavior correlated with their significant volume expansion during cycling. Here we report a combination of Co3O4@CoNiO2 (CO@CNO) nanorod and nanosheet composites and elastically conductive PPy film grown on conductive Ni foam, and construct an unhindered transportation and diffusion path for electron and Li-ion. After 100 cycles, the reversible capacity of this novel CO@CNO@PPy maintains at 1229 mAh g−1, while CO@CNO just matins at 520 mAh g−1. After the first charge-discharge process, CO@CNO@PPy and CO@CNO electrodes correspond to average capacity fade rate of 0.23% and 0.54% per cycle. The improved property can be ascribed to the reduced resistance and enhanced diffusion coefficient of Li-ion because of the unique architecture and conductive PPy film coating, which promotes the conductivity of electrodes, and alleviate the structure destruction. These prominent electrochemical performances indicate a hopeful application of the CO@CNO@PPy nanocomposite in next-generation high-energy LIBs.