(23f) A Facile Hydrothermal Route to Fe2O3 with Conductive Additives As Composite Anode for Lithium Ion Batteries

Transition metal oxides have been intensively investigated as anode materials for lithium ion batteries (LIBs) due to their high theoretical capacity, natural abundance, low cost, ease of fabrication and environmental friendliness. However, poor conductivity and large volume change of such materials during electrochemical reaction strongly limit their practical application. To overcome these disadvantages, research has been focusing on the following aspects: (i) synthesis of nanosized metal oxide materials with large surface area, which can greatly enhance the contact area between the active material and electrolyte and shorten the diffusion path of lithium ions; (ii) novel morphologies of the microstructures such as hollow sphere, nanorod, spindle, nanotube, nanocube proposed as means of advancing superior electrochemical kinetics and remarkable structural stability; and (iii) composites of metal oxides with carbon or polymer additives designed to improve the conductivity and the electrochemical performances.

Herein, we report a facile hydrothermal route for the synthesis of Fe₂O₃ nanoparticles and their composites with conductive additives, reduced graphite oxide (rGO) and conductive polymer of Poly(3,4-ethylenedioxythiophene) Polystyrene sulfonate (PEDOT:PSS), as anode materials for LIBs. The addition of conductive polymer layer on Fe₂O₃ nanoparticles may facilitate the electron transport but hinders the Li⁺ ion insertion at higher current density. On the other hand, Fe₂O₃@rGO prepared by growing Fe₂O₃ nanoparticles directly on rGO sheets shows the best electrochemical behavior due to a beneficial combination of the rGO nanosheets partially wrapped Fe₂O₃ nanoparticles which facilitates both the electron transport and the Li⁺ ion insertion. The enhanced conductivity of the composites was proved. The high specific capacity and stable rate performance of Fe₂O₃@rGO composites encourages their further application as potential candidate for the anode materials in LIBs. These results will be helpful in further elucidation of the role of conductive additives in improving the electrochemical performance of Fe₂O₃ based composite anodes and this simple synthetic strategy may be applied for the large scale production of metal oxides with conductive additives for LIBs.