Fabrication and characterization of double protective carbon aerogel (CA)/α-Fe2O3@Polypyrrole (PPy) composites as an anode material for high performance lithium ion batteries

Carbon aerogel (CA)/alpha-Fe2O3@Polypyrrole (PPy) composites with double protective structure are synthesized via a solvothermal method with further in-situ polymerization of polypyrrole. The structure, morphology, loading content of alpha-Fe2O3 in composite and electrochemical properties are investigated by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy, thermogravimetry, constant current charge/discharge tests, cyclic voltammetry tests and electrochemical impedance spectroscopy. The results show alpha-Fe2O3 directional grows on the inner carbon aerogel while embeds in the outer PPy layer. As an anode material of lithium ion batteries, the CA/alpha-Fe2O3@PPy composite electrode exhibits more excellent cycling stability and rate capability than that of the bare alpha-Fe2O3 and CA/alpha-Fe2O3. The unique structure is responsible for the excellent electrochemical performance, which not only provides double protection against the aggregation and volume changes of alpha-Fe2O3 particles, but also ensures favorable transport kinetics for both electron and lithium ion.