Preparation, structural, and characterizations of SnO <sub>2</sub> ‐coated TiNb <sub>2</sub> O <sub>7</sub> anode materials for lithium‐ion batteries
Kai‐Hsiang Liang, Karan Kumar Gupta, Chung‐Hsin Lu, Sudipta Som
Abstract
Abstract SnO 2 ‐coated TiNb 2 O 7 powders were synthesized via the solution coating method in the present research. The SnO 2 layers with a thickness of 3–5 nm were homogeneously coated on the surface of TiNb 2 O 7 particles. TiNb 2 O 7 coated with SnO 2 of 5 mol% with high Li + diffusion coefficient delivered the discharge capacity of 319.5 mAh/g, which was 6.6% higher than that of the non‐coated samples. The enhancement of capacity for the coated TiNb 2 O 7 was owing to the low charge‐transfer resistance of 17.5 Ω in contrary to the non‐coated TiNb 2 O 7 (27.8 Ω). SnO 2 ‐coated TiNb 2 O 7 possessed an improved capacity retention of 85.2% at 5 C after 100 cycles, superior to the non‐coated TiNb 2 O 7 (79.8%). On the other hand, the excessive amounts of SnO 2 coating led to the reduction in the capacity of the prepared samples. The excessive amounts of SnO 2 layers suppressed the Li + diffusion and increased the charge‐transfer resistance. The obtained results in this study indicated that coating of TiNb 2 O 7 with appropriate amounts of SnO 2 significantly improved the electrochemical performance of TiNb 2 O 7 .