高容量锂电池负极材料TiNb2O7的合成及其机理

将TiNb₂O₇的前驱体在不同温度(400℃、800℃、900℃、1000℃和1100℃)煅烧，用固相合成法制备TiNb₂O₇负极材料并对其样品进行了TG-DSC、XRD和SEM表征和电化学性能测试。结果表明：在900℃煅烧前驱体，锐钛矿与Nb₂O₅反应的主要产物为Ti₂Nb₁₀O₂₉。Ti₂Nb₁₀O₂₉与金红石反应生成了TiNb₂O₇，生成纯单斜相TiNb₂O₇的最佳条件为在1100℃煅烧6 h。TiNb₂O₇负极材料在0.2C电流密度时初始容量为278.4 mAh/g，初始库伦效率为82.9%。TiNb₂O₇具有良好的倍率容量，在1C循环100次后容量保持率为89%。

Synthesis and Formation Mechanism of Lithium Battery High-Capacity Anode Material TiNb2O7

The precursor of TiNb₂O₇ is prepared via solid-phase synthesis with anatase and Nb₂O₅ as raw materials and then calcinated at 400℃, 800℃, 900℃, 1000℃ and 1100℃ respectively in air to prepare TiNb₂O₇ as electrode materials. The prepared materials are characterized by means of thermo-gravimetric analyzer, differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical test. The results show that the main reaction products of anatase and Nb₂O₅ at 900℃ is Ti₂Nb₁₀O₂₉. TiNb₂O₇ is obtained by the reaction of Ti₂Nb₁₀O₂₉ and rutile. The optimum calcination condition of pure monoclinic TiNb₂O₇ is 1100℃ for 8 h. TiNb₂O₇ anode material has an initial capacity of 278.4 mAh/g at 0.2C and the initial coulombic efficiency is 82.9%. In the meantime, TiNb₂O₇ has a good rate capacity, which can still reach 89% after 100 cycles at 1C rate.