Chromium-Modified Li4Ti5O12 with a Synergistic Effect of Bulk Doping, Surface Coating, and Size Reducing
Chromium-Modified Li4Ti5O12 with a Synergistic Effect of Bulk Doping, Surface Coating, and Size Reducing
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具有体掺杂、表面涂层和尺寸减小协同效应的铬改性 Li4Ti5O12
DOI：
10.1021/acsami.6b07742
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发表时间：
2016
影响因子：
9.5
通讯作者：
Xiang Hongfa
中科院分区：
文献类型：
--
作者：
Zou Hailin;Liang Xin;Feng Xuyong;Xiang Hongfa
体掺杂、表面包覆和尺寸减小是改善Li 4 Ti 5 O 12（LTO）电化学性能的三种策略。本工作采用溶胶-凝胶法合成了具有体掺杂、表面包覆和尺寸减小协同效应的铬改性LTO。X射线衍射（XRD）和拉曼光谱分析表明，Cr掺杂到了LTO体晶格中，有效地抑制了TiO 2杂质的生成。透射电子显微镜（TEM）和X射线光电子能谱（XPS）分析证实了Li 2CrO 4在LTO电极表面的包覆，降低了电极的阻抗。更重要的是，由于Li 2CrO 4表面层的保护和Cr原子对LTO晶格中长程有序的抑制，LTO颗粒的尺寸可以从亚微米级显著减小到纳米级。Li 4-xCr 3xTi 5 - 2xO 12（x= 0.1）作为负极材料，在10 °C下提供141 mAh g-1的可逆容量，并且在1 °C下在1000次循环后提供超过155 mAh g-1。因此，溶胶-凝胶法制备的Cr改性Li 4 Ti 5 O 12在高功率、长寿命锂离子电池中具有潜在的应用价值。
Bulk doping, surface coating, and size reducing are three strategies for improving the electrochemical properties of Li4Ti5O12(LTO). In this work, chromium (Cr)-modified LTO with a synergistic effect of bulk doping, surface coating, and size reducing is synthesized by a facile sol–gel method. X-ray diffraction (XRD) and Raman analysis prove that Cr dopes into the LTO bulk lattice, which effectively inhibits the generation of TiO2impurities. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) verifies the surface coating of Li2CrO4on the LTO surface, which decreases impedance of the LTO electrode. More importantly, the size of LTO particles can be significantly reduced from submicroscale to nanoscale as a result of the protection of the Li2CrO4surface layer and the suppression from Cr atoms on the long-range order in the LTO lattice. As anode material, Li4-xCr3xTi5–2xO12(x= 0.1) delivers a reversible capacity of 141 mAh g–1at 10 °C, and over 155 mAh g–1at 1 °C after 1000 cycles. Therefore, the Cr-modified Li4Ti5O12prepared via a sol–gel method has potential for applications in high-power, long-life lithium-ion batteries.