High Performance Ti3+ Self-Doped Li4Ti5O12 Anode Materials Synthesized by an Electrochemical Method in Molten Salt

Abstract

A simple synthesis for the Ti3+-doped, small Li4Ti5O12 is favorable for its application as an anode material of lithium-ion batteries. This study presents a direct synthesis method of high-performance Li4Ti5O12 (LTO-Ti) with the Ti3+ self-doped and uniformly small in size. It is carried out by the redox of an electrochemical electrode pair of Ti and Fe2O3 at a constant potential in molten KCl-LiCl salt with Li2CO3. The synthesis mechanism and the effect of synthesis conditions on the formation and properties of LTO-Ti were investigated in detail. The LTO-Ti with an average size of approximately 400 nm is prepared by the ionic level synthesis method, and exhibits a superior specific capacity of 130.5 mAh·g−1 at 10 C current density, which is 73.6% of its average specific capacity at 1 C. Moreover, it also shows good cycling stability with a specific capacity of 127.2 mAh·g−1 after 1000 cycles at 5 C (capacity retention of 96.9%). This synthesis is secure and prospective.