Electrostatic spray deposition of porous Fe_2O_3 thin films as anode material with improved electrochemical performance for lithium-ion batteries

摘要

Iron oxide materials are attractive anode materials for lithium-ion batteries for their high capacity and low cost compared with graphite and most of other transition metal oxides. Porous carbon-free α-Fe_2O_3 films with two types of pore size distribution were prepared by electrostatic spray deposition, and they were characterized by X-ray diffraction, scanning electron microscopy and X-ray absorption near-edge spectroscopy. The 200℃-deposited thin film exhibits a high reversible capacity of up to 1080 mAhg~(-1), while the initial capacity loss is at a remarkable low level (19.8%). Besides, the energy efficiency and energy specific average potential (E_(av)) of the Fe_2O_3 films during charge/discharge process were also investigated. The results indicate that the porous α-Fe_2O_3 films have significantly higher energy density than Li_4Ti_5O_(12) while it has a similar E_(av) of about 1.5 V. Due to the porous structure that can buffer the volume changes during lithium intercalation/de-intercalation, the films exhibit stable cycling performance. As a potential anode material for high performance lithium-ion batteries that can be applied on electric vehicle and energy storage, rate capability and electrochemical performance under high-low temperatures were also investigated.