High rate capability and long cycle stability of Fe2O3/MgFe2O4 anode material synthesized by gel-cast processing

Abstract

In this paper, coralloid Fe2O3/MgFe2O4 composite was synthesized as anode material for lithium ion batteries via a simple gel-cast method. The Fe2O3/MgFe2O4 composite exhibits much better electrochemical performance than pure Fe2O3 and MgFe2O4. Capacity of the Fe2O3/MgFe2O4 composite maintains an anomalous increase to 1800mAhg−1 (at about the 300th cycle), and stabilizes at 1700mAhg−1 until 500 cycles at a current density of 1Ag−1. Even cycled at a current density of 20Ag−1, a capacity of 760mAhg−1 can still be achieved. The excellent performances may be attributed to the enlarged crystal lattice and the relatively lower bonding energy of FeO bond. Furthermore, capacity rise phenomenon of the Fe2O3/MgFe2O4 composite was studied. Results show that both interfacial lithium storage and the polymeric/gel-like layer contribute to that.