Single-Crystalline TiO2(B) Nanobelts with Unusual Large Exposed {100} Facets and Enhanced Li-Storage Capacity |
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| Authors: | Qiang Wang Lei Shen Tong Xue Gao Cheng Cheng Zhi Huang Hong Jin Fan Yuan Ping Feng |
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| Affiliation: | 1. School of Materials and Energy, Chongqing Key Laboratory for Advanced Materials and Technologies of Clean Energies, Southwest University, Chongqing, 400715 P. R. China;2. Department of Mechanical Engineering, National University of Singapore, Singapore, 117575 Singapore;3. School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371 Singapore;4. Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, Southwest University, Chongqing, 400715 P. R. China;5. Department of Physics, National University of Singapore, Singapore, 117542 Singapore |
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| Abstract: | The {100} facet of single-crystalline TiO2(B) is an ideal platform for inserting Li ions, but it is hard to be obtained due to its high surface energy. Here, the single-crystalline TiO2(B) nanobelts from H2Ti3O7 with nearly 70% {100} facets exposed are synthesized, which significantly enhances Li-storage capacity. The first-principle calculations demonstrate an ab in-plane 2D diffusion through the exposed {100} facets. As a consequence, the nanobelts can significantly accommodate Li ions in LiTiO2 formula with specific capacity up to 335 mAh g−1, which is in good agreement with the electrochemical characterizations. Coating with conductive and protective poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), the cut-off discharge voltage is as low as 0.5 V, leading to a capacity of 160.7 mAh g−1 after 1500 cycles with a retention rate of 66% at 1C. This work provides a practical strategy to increase the Li-ion capacity and cycle stability by tailoring the crystal orientation and nanostructures. |
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| Keywords: | crystal facets first principles lithium-ion batteries lithium-ion diffusion TiO2(B) |
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