Boosting Li-ion storage kinetics via constructing layered TiO2 anode

Due to the typical intercalation-deintercalation mechanism, TiO2 holds great promise as a sustainable anode for next-generation lithium-ion batteries (LIBs). However, commercial TiO2 (C–TiO2) is granular and shows slow ionic conductivity, which greatly hinders its development due to sluggish kinetics, leading to low reversible capacity and inferior rate capability. In this study, a two-dimensional layered TiO2 (L-TiO2) anode is prepared via a one-step calcination process, which can effectively shorten the lithium ions diffusion path and improve its lithium ions conductivity. We elucidated the enhanced electrochemical performance of L-TiO2 as an anode in LIBs through pseudocapacitive acceleration of lithium ions intercalation and deintercalation using various characterization techniques, including different scan rate cyclic voltammetry tests, in situ electrochemical impedance spectroscopy, in situ Raman spectroscopy, and in situ X-ray diffraction. In comparison to C–TiO2 material, L-TiO2 material showcases remarkable electrochemical performance, achieving a capacity of 166 mAh/g after 100 cycles at 0.1 C. Additionally, the lithium-ion diffusion coefficient calculated for the L-TiO2 is two orders of magnitude greater, underscoring its potential as a negative electrode material for LIBs.

凭借典型的嵌入-脱嵌机制，二氧化钛（TiO₂）作为下一代锂离子电池（LIBs）的可持续负极材料极具应用前景。然而，商用二氧化钛（C–TiO₂）呈颗粒状，离子电导率偏低，因动力学迟缓严重制约其发展，进而导致可逆比容量较低且倍率性能欠佳。本研究通过一步煅烧法制备出二维层状二氧化钛（L–TiO₂）负极，该材料可有效缩短锂离子扩散路径，提升锂离子电导率。本研究借助多种表征手段，包括不同扫速循环伏安测试、原位电化学阻抗谱、原位拉曼光谱及原位X射线衍射，通过锂离子嵌入-脱嵌的赝电容加速机制，阐明了L–TiO₂用作锂离子电池负极时的优异电化学性能。与商用二氧化钛（C–TiO₂）相比，L–TiO₂展现出更为优异的电化学性能：在0.1 C倍率下循环100次后，其比容量可达166 mAh/g。此外，L–TiO₂的锂离子扩散系数计算值高出两个数量级，进一步凸显其作为锂离子电池负极材料的应用潜力。