Wang Rui, Cao Xiaoyu, Zhao Dexing, Zhu Limin, Xie Lingling, Li Jingjing, Miao Yongxia
School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, PR China.
Key Laboratory of High Specific Energy Materials for Electrochemical Power Sources of Zhengzhou City, Henan University of Technology, Zhengzhou 450001, PR China.
ACS Appl Mater Interfaces. 2020 Sep 2;12(35):39170-39180. doi: 10.1021/acsami.0c10603. Epub 2020 Aug 18.
The low electronic conductivity of spinel-structured LiTiO could be improved by introducing CuVO. Herein, several LiTiO/CuVO composites with different CuVO contents have been successfully prepared by a facile liquid-phase dispersion technique. The amount of CuVO in composites is shown to affect the particle size and electrochemical performances of LiTiO. The LiTiO/CuVO composite prepared with a 5 wt % CuVO content (referred to as 5 wt % LiTiO/CuVO) exhibits the best electrochemical performances among all the LiTiO/CuVO composites. The initial discharge/charge capacities of the 5 wt % LiTiO/CuVO composite reach 241.1/199.8 mAh g and retain at 136.8/135.7 mAh g over 500 cycles at 30 mA g between 1.0 and 3.0 V. In addition, initial discharge/charge capacities of the 5 wt % LiTiO/CuVO composite amount to 129.8/90.5 mAh g even at 1200 mA g with maintained discharge/charge capacities of 71.1/71.1 mAh g over 2500 cycles, which are superior to the pristine LiTiO in all cases. The detailed electrode kinetic analysis reveals that the introduction of the CuVO phase can enhance the lithium-ion transferring rate and cycling stability of LiTiO. The enhanced lithium-storage mechanism of the 5 wt % LiTiO/CuVO composite is clarified by X-ray diffraction (XRD) analysis. The acquired data confirms that formation of small amounts of metallic Cu during discharge/charge processes highly enhance the electronic conductivity and decreases the charge-transfer resistance of LiTiO. In sum, the as-obtained 5 wt % LiTiO/CuVO composite has potential for future construction of high-rate and long-lifespan anode materials for Li-ion batteries. The work also provides an innovative route to improve electrochemical performances of LiTiO.
通过引入CuVO可以提高尖晶石结构LiTiO的低电子电导率。在此，通过简便的液相分散技术成功制备了几种不同CuVO含量的LiTiO/CuVO复合材料。结果表明，复合材料中CuVO的含量会影响LiTiO的粒径和电化学性能。含5 wt% CuVO（称为5 wt% LiTiO/CuVO）的LiTiO/CuVO复合材料在所有LiTiO/CuVO复合材料中表现出最佳的电化学性能。5 wt% LiTiO/CuVO复合材料的首次充放电容量分别达到241.1/199.8 mAh g，在1.0至3.0 V之间以30 mA g的电流密度循环500次后保持在136.8/135.7 mAh g。此外，5 wt% LiTiO/CuVO复合材料即使在1200 mA g的电流密度下首次充放电容量也达到129.8/90.5 mAh g，在2500次循环中保持充放电容量为71.1/71.1 mAh g，在所有情况下均优于原始LiTiO。详细的电极动力学分析表明，CuVO相的引入可以提高LiTiO的锂离子传输速率和循环稳定性。通过X射线衍射（XRD）分析阐明了5 wt% LiTiO/CuVO复合材料增强的储锂机制。获得的数据证实，在充放电过程中形成少量金属Cu可显著提高LiTiO的电子电导率并降低电荷转移电阻。总之，所制备的5 wt% LiTiO/CuVO复合材料具有用于未来构建锂离子电池高倍率和长寿命负极材料的潜力。这项工作还为提高LiTiO的电化学性能提供了一条创新途径。
