The lithium titanate defect spinel, Li4Ti5O12 (LTO), is a promising “zero-strain” anode material for lithium-ion batteries in cycling-demanding applications. However, the low-rate capability limits its range of applications. Surface modifications, for example, coating and defect engineering, play an intriguing role in interfacial electrochemical processes. Herein, a novel synthesis of highly oxygen-deficient “defective-LTO” anode material with high-rate performance is reported. It is synthesized using conventional precursors via a one-pot thermal reduction process. A high level of oxygen vacancies of ≈6.5 at% and conformal amorphous carbon coating are achieved simultaneously, resulting in a compounding effect for a high discharge capacity of 123 mAh g−1 with Coulombic efficiency of 99.8% at 10 C-rate. Ab initio calculations foresight that oxygen vacancies increase the electron donor density of the neighboring titanium atoms, while conformal amorphous carbon significantly lowers interfacial charge-transfer resistance. The formation mechanism, as well as the origin of enhanced electrochemical properties, is elaborated in this paper.
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering