Synthesis and Mechanism of High Structural Stability of Nickel-Rich Cathode Materials by Adjusting Li-Excess
| Autor: | Aichun Dou, Mingru Su, Tao Wan, Dewei Chu, Yunjian Liu, Xingyu Qu, Yu Zhou, Xiaoqi Peng, Zhenlu Yu |
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| Rok vydání: | 2020 |
| Předmět: |
Diffraction
Materials science Analytical chemistry chemistry.chemical_element 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Focused ion beam Cathode 0104 chemical sciences law.invention Nickel Transition metal chemistry Transmission electron microscopy law Structural stability Particle General Materials Science 0210 nano-technology |
| Zdroj: | ACS applied materialsinterfaces. 12(36) |
| ISSN: | 1944-8252 |
| Popis: | It has been a long-term challenge to improve the phase stability of Ni-rich LiNixMnyCo1-x-yO2 (x ≥ 0.6) transition metal (TM) oxides for large-scale applications. Herein, a new structure engineering strategy is utilized to optimize the structural arrangement of Li1+x(Ni0.88Mn0.06Co0.06)1-xO2 (NMC88) with a different Li-excess content. It was found that structure stability and particle sizes can be tuned with suitable Li-excess contents. NMC88 with an actual Li-excess of 2.7% (x = 0.027, Li/TM = 1.055) exhibits a high discharge capacity (209.1 mAh g-1 at 3.0-4.3 V, 0.1 C) and maintains 91.7% after the 100th cycle at 1 C compared with the NMC88 sample free of Li-excess. It also performs a delayed voltage decay and a good rate capacity, delivering 145.8 mAh g-1 at a high rate of 10 C. Multiscale characterization technologies including ex/in situ X-ray diffraction (XRD), focused ion beam (FIB) cutting-scanning electronic microscopy (SEM), and transmission electron microscopy (TEM) results show that a proper Li-excess (2.7%) content contributes to the formation of a broader Li slab, optimized cation mixing ratio, and even particle sizes. Therefore, NMC88 with a proper Li-excess is a good choice for next-generation cathode materials. |
| Databáze: | OpenAIRE |
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