Reduced graphene oxide/Fe-phthalocyanine nanosphere cathodes for lithium-ion batteries

Organic–inorganic composites show great potential for organic rechargeable lithium-ion batteries. In this work, two-dimensional phthalocyanine molecules were converted into hybrid nanoparticles with a porous structure and bound to a conductive graphene layer to act as a cathode material. The conductivity of this reduced graphene oxide/Fe-phthalocyanine (rGO/FePc) composite is improved through good interfacial connections and internal polymerization. The FePc spheres were shaped with the assistance of Fe3O4 and immobilized between the layers of reduced graphene oxide (rGO). The electrochemical properties of the organic–inorganic composites were investigated by testing in a lithium-ion cell. A high discharge capacity of 186 mAh g−1 was maintained after 100 cycles at 300 mA g−1, which demonstrates a significant improvement in the cycle life compared to previous reports of phthalocyanine-based electrochemical energy storage behaviour.