Electrochemical characterizations of carbon decorated tin doped lithium titanate for lithium-ion battery anode applications

Lithium titanate (Li4Ti5O12) anode materials are widely popular because of their exceptional structural properties that could offer extremely long life and high current rate with safe operation. In-depth research works have been going on to mitigate the limiting factors like poor conduction and diffusion of lithium titanate for the electrode applications in the lithium-ion battery. Elemental doping and surface coating were found to be promising methods to overcome these challenges and enhance the capacity for widespread application. Herein, ex-situ carbon-coated tin (Sn4+) doped lithium titanate was synthesized via conventional solid-state synthesis. Its electrochemical performances were analyzed and compared with its pristine phase by making half cells with lithium. The results were highly promising as the Li4Sn0.05Ti4.95O12 with 5 wt% carbon coating exhibited significantly reduced cell impedance (Rct = 49.48 Ω), enhanced electrode lithium-ion diffusion coefficient (D = 2.40×10−11 cm2 s−1), and superior specific capacity (Q = 173.1 mAh/g at 0.1 C) over pristine lithium titanate (Rct = 274.2 Ω, D = 2.71×10−12 cm2 s−1, and Q = 145 mAh/g). The cell could also run for 1000 cycles with minimum capacity fade (82 % retention) at a 1 C rate.