Scalable synthesis of γ-Fe2O3/CNT composite as high-performance anode material for lithium-ion batteries

Abstract

Maghemite (γ-Fe2O3) is considered more stable than α-Fe2O3 as an anode material for lithium-ion batteries because it has adequate vacancy sites and lower surface energy. However, the facile synthesis of γ-Fe2O3 is still a technological challenge. In this work, a composite based of γ-Fe2O3 and carbon nanotubes (CNTs) is successfully synthesized by a facile one-step direct current arc-discharge approach. Under an atmosphere of low-pressure air, Fe particles act as catalysts for carbon nanotube growth and are subsequently oxidized in situ to γ-Fe2O3 with a mean diameter of about 10 nm deposited on the carbon nanotubes. The as-synthesized γ-Fe2O3/CNT composite shows a stable cycling capacity of 1186.8 mAh g−1 after 400 cycles at 200 mA g−1. In addition, the γ-Fe2O3/CNT composite delivers excellent rate performance of 611.8 mAh g−1 at 4000 mA g−1 and a high reversible capacity of 518.5 mAh g−1 remains after 300 cycles at 4000 mA g−1. The highly stable γ-Fe2O3 particles and highly conductive carbon nanotubes are the key factors that provide the extraordinary performance of the composite. Most importantly, γ-Fe2O3/CNT composite and the arc-discharge fabrication method hold great potential for further industrial applications in energy storage.