Ko, Wonseok Yoo, Jung-Keun Park, Hyunyoung Lee, Yongseok Kang, Inyeong Kang, Jungmin Jo, Jae Hyeon Choi, Ji Ung Hong, Jihyun Myung, Seung-Taek Kim, Jongsoon 2024-01-19T16:04:40Z 2024-01-19T16:04:40Z 2021-09-02 2020-11 2211-2855 https://pubs.kist.re.kr/handle/201004/117905 We report a tunnel-type V1.5Cr0.5O4.5H/carbon-nanotube (T-VCr/C) nanocomposite as a new high-energy cathode material for sodium-ion batteries. Structural analyses using Rietveld refinement and bond-valence-energy landscape analysis based on X-ray diffraction reveal the Na+ diffusion paths and possible atomic sizes of Na+ in the V1.5Cr0.5O4.5H structure. Through combined studies using first-principles calculations and various experimental techniques, we confirm that the T-VCr/C nanocomposite delivers a large specific capacity of similar to 306 mAh g(-1), corresponding to 2 mol Na+ de/intercalation at 15 mA g(-1), with an average operation voltage of similar to 2.5 V (vs. Na+/Na) in the voltage range of 1.0-4.0 V based on reversible V3+/V4+ and Cr3+/Cr4+ redox reactions. Even at 900 mA g(-1), the T-VCr/C nanocomposite retains a specific capacity of similar to 214.9 mAh g(-1), corresponding to similar to 70.2% of the capacity measured at 15 mA g(-1). Furthermore, over 100 cycles at 300 mA g(-1), the T-VCr/C nanocomposite exhibits capacity retention of similar to 77.1% compared with the initial capacity. Operand /ex-situ X-ray diffraction and X-ray absorption spectroscopy analyses reveal the small structural change of NaxV1.5Cr0.5O4.5H (0 <= x <= 2) during Na+ de/intercalation based on V4+/V3+ and Cr4+/Cr3+ redox reaction, leading to the outstanding electrochemical performance of the T-VCr/C nanocomposite. English ELSEVIER HIGH-CAPACITY NEGATIVE ELECTRODE SODIUM INTERCALATION MECHANISM NANORODS CARBON ANODE FILMS CO3O4 Exceptionally high-energy tunnel-type V1.5Cr0.5O4.5H nanocomposite as a novel cathode for Na-ion batteries Article 10.1016/j.nanoen.2020.105175 1 NANO ENERGY, v.77 NANO ENERGY 77 scie scopus 000581738300065 2-s2.0-85088654181 Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Chemistry Science & Technology - Other Topics Materials Science Physics Article HIGH-CAPACITY NEGATIVE ELECTRODE SODIUM INTERCALATION MECHANISM NANORODS CARBON ANODE FILMS CO3O4 Sodium-ion batteries Cathode material Carbon-nanotube First-principles calculations Operando