Solvothermal synthesis of TiNb2O7 microspheres as anodic materials for high-performance lithium–ion batteries

TiNb 2 O 7 (TNO) has been regarded as a promising anode material for high-power lithium–ion batteries due to its high theoretical capacity and work voltage (387.6 mA h g −1 , 1.6 V vs. Li + /Li). Herein, a series of microspherical TNO anode materials are synthesized by a facile solvothermal method, and the effect of solvothermal time on the microstructure and electrochemical performance is investigated. Specifically, when the solvothermal time is 12 h, the TNO microsphere (TNO-12) exhibits higher specific surface area and more reasonable pore size distribution. As a result, TNO-12 anode delivers a high reversible discharge capacity of 299.87 mA h g −1 with a superior initial coulombic efficiency above 98.5%, excellent cycling capacity retention of 80.15% after 100 cycles at 0.5 C (150 mA g −1 ), and good rate performance at 0.1–2 C. Most importantly, the full cell constructed with TNO anode and commercial oxide cathode (LiNi 0.6 Mn 0.4 O 2 /LiMn 2 O 4 with a mass ratio of 85: 15) exhibits excellent cycling stability at high current densities (79.14% after 100 cycles at 0.5 C). This study optimizes the synthesis process for high-performance microspherical TNOs, providing new insights for the next generation of commercial anodes.