Porosity‐Controlled TiNb2O7 Microspheres with Partial Nitridation as A Practical Negative Electrode for High‐Power Lithium‐Ion Batteries |
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Authors: | Hyunjung Park Hao Bin Wu Taeseup Song Xiong Wen Lou Ungyu Paik |
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Institution: | 1. WCU Department of Energy Engineering, Hanyang University, Seoul, Korea;2. School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore;3. Department of Materials Science and Engineering, Hanyang University, Seoul, Korea |
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Abstract: | Titanium niobium oxide (TiNb2O7) has been recognized as a promising anode material for lithium‐ion batteries (LIBs) in view of its potential to operate at high rates with improved safety and high theoretical capacity of 387 mAh g?1. However, it suffers from poor Li+ ion diffusivity and low electronic conductivity originated from its wide band gap energy (Eg > 2 eV). Here, porous TiNb2O7 microspheres (PTNO MSs) are prepared via a facile solvothermal reaction. PTNO MSs have a particle size of ≈1.2 μm and controllable pore sizes in the range of 5–35 nm. Ammonia gas nitridation treatment is conducted on PTNO MSs to introduce conducting Ti1?xNbxN layer on the surface and form nitridated PTNO (NPTNO) MSs. The porous structure and conducting Ti1?xNbxN layer enhance the transport kinetics associated with Li+ ions and electrons, which leads to significant improvement in electrochemical performance. As a result, the NPTNO electrode shows a high discharge capacity of ≈265 mAh g?1, remarkable rate capability (≈143 mAh g?1 at 100 C) and durable long‐term cyclability (≈91% capacity retention over 1000 cycles at 5 C). These results demonstrate the great potential of TiNb2O7 as a practical high‐rate anode material for LIBs. |
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Keywords: | anodes lithium‐ion batteries microspheres TiNb2O7 |
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