Ti2Nb10O29–x mesoporous microspheres as promising anode materials for high-performance lithium-ion batteries

• Published in: Journal of power sources Vol. 362; pp. 250 - 257
• Main Authors: Deng, Shengjue, Luo, Zhibin, Liu, Yating, Lou, Xiaoming, Lin, Chunfu, Yang, Chao, Zhao, Hua, Zheng, Peng, Sun, Zhongliang, Li, Jianbao, Wang, Ning, Wu, Hui
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.09.2017
• Subjects: Anode; Crystal-structure modification; Electrochemical performance; Lithium-ion battery; Mesoporous microsphere; Ti2Nb10O29; Lithium-ion battery; Electrochemical performance; Ti2Nb10O29; Mesoporous microsphere; Crystal-structure modification; Anode
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2017.07.039

Ti2Nb10O29 has recently been reported as a promising anode material for lithium-ion batteries. However, its poor electronic conductivity and insufficient Li+-ion diffusion coefficient significantly limit its rate capability. To tackle this issue, a strategy combining nanosizing and crystal-structure modification is employed. Ti2Nb10O29–x mesoporous microspheres with a sphere-size range of 0.5–4 μm are prepared by a one-step solvothermal method followed by thermal treatment in N2. These Ti2Nb10O29–x mesoporous microspheres exhibit primary nanoparticles, a large specific surface area (22.9 m2 g−1) and suitable pore sizes, leading to easy electron/Li+-ion transport and good interfacial reactivity. Ti2Nb10O29–x shows a defective shear ReO3 crystal structure with O2− vacancies and an increased unit cell volume, resulting in its increased Li+-ion diffusion coefficient. Besides Ti4+ and Nb5+ ions, Ti2Nb10O29–x comprises Nb4+ ions with unpaired 4d electrons, which significantly increase its electronic conductivity. As a result of these improvements, the Ti2Nb10O29–x mesoporous microspheres reveal superior electrochemical performances in term of large reversible specific capacity (309 mAh g−1 at 0.1 C), outstanding rate capability (235 mAh g−1 at 40 C) and durable cyclic stability (capacity retention of 92.1% over 100 cycles at 10 C). [Display omitted] •A combined method is used to improve the electrochemical properties of Ti2Nb10O29.•Conductive Ti2Nb10O29–x mesoporous microspheres are solvothermally synthesized.•Ti2Nb10O29–x exhibits Nb4+ ions, O2− vacancies and an increased unit cell volume.•Ti2Nb10O29–x mesoporous microspheres outperform other Ti2Nb10O29 anode materials.