Nano-TiNb2O7/carbon nanotubes composite anode for enhanced lithium-ion storage. (10th January 2018)

• Record Type: Journal Article
• Authors: Lin, Chunfu; Hu, Lei; Cheng, Chuanbing; Sun, Kai; Guo, Xingkui; Shao, Qian; Li, Jianbao; Wang, Ning; Guo, Zhanhu
• Is Part Of: Electrochimica acta. Volume 260(2018)
• Page Start: 65
• Page End: 72
• Publication Date: 2018-01-10
• Subjects: Lithium-ion battery -- TiNb2O7 anode material -- Combined method -- Electrical conductivity -- Electrochemical performance; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2017.11.051
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Although with a large capacity, TiNb2 O7 as an anode material of lithium-ion batteries suffers from a poor rate capability. To solve this challenge, nano-TiNb2 O7 and its carbon nanotube (CNT) nanocomposites were prepared by direct hydrolysis of TiNb2 O7 /CNTs suspension followed by calcination in air and N2, respectively. The TiNb2 O7 nanoparticles in the composites have a Ti2 Nb10 O29 -type crystal structure with O 2− vacancies and lower-valence cations, leading to improved Li + -ion diffusion coefficient and increased electronic conductivity in TiNb2 O7 . The evenly distributed CNTs have good contact with the TiNb2 O7 particles, thereby reducing their particle sizes and improving the electrical conduction. As a result of these improvements, the nanocomposites present outstanding electrochemical performances. For example, it delivers a large reversible capacity (346 mAh g −1 at 0.1 C) and a prominent rate capability (still 163 mAh g −1 at the ultra-large current rate of 30 C). Exceptional cyclic stability is also demonstrated with over 100 cycles at 10 C with large capacity retention of 97.6%. These results reveal that the nano-TiNb2 O7 /CNTs composites can be a promising anode material for lithium-ion batteries of electric vehicles. Graphical abstract: Highlights: Structure modification, compositing and nanosizing synergistically improve TiNb2 O7 . TiNb2 O7 in the composites unexpectedly has a Ti2 Nb10 O29 -type structure with defects. Improved intrinsic/extrinsic conduction and smaller particle sizes are achieved. Nano-TiNb2 O7 /CNTs show a large capacity, outstanding rate and cyclic performances. Nano-TiNb2 O7 /CNTs may be applied to lithium-ion batteries of electric vehicles.