厦门大学AFM: 通过包覆-掺杂-微观结构调控三合一策略增强高镍LiNi0.9Co0.05Mn0.05O2正极的结构和界面稳定性

通过涂层-掺杂-微结构调控三合一策略增强高镍LiNi_0.9Co_0.05Mn_0.05O₂正极的结构和界面稳定性

第一作者：邹跃

通讯作者：乔羽*，鲍骏*，孙世刚*

单位：中国科学技术大学国家同步辐射实验室，厦门大学化学化工学院，中国散裂中子源

图1. Sb₂Se₃改性NCM90正极的机理示意图。

要点一：Sb₂Se₃改性NCM90正极的结构及界面表征

Figure 1. a) HRTEM images of Sb₂Se₃-NCM90 cathode and the corresponding FFT conversions of highlighted region Ⅰ (Layered structure) and Ⅱ (Surface coating). Beyond that, the HAADF image and the corresponding EDS mapping (Ni/Co/Mn/Sb/Se) of Sb₂Se₃-NCM90 cathode are exhibited on the bottom. b, c) Rietveld refinement of XRD and NPD for Sb₂Se₃-NCM90. d) The surface and cross-section morphology of Sb₂Se₃-NCM90 cathode characterized by SEM and the corresponding EDS mapping (Ni/Co/Mn/Sb/Se/O) of the selected region. XPS pattern of e) Ni 2p, f) Sb 3d and g) Se 3d for Sb₂Se₃NCM90 cathode. h) TOF-SIMS measurements: depth etching of negative ion fragments (Ni^-, Sb^-, Se^-) for Sb2Se3-NCM90 cathode.

Figure 2. Charge/discharge curves of a) NCM90 and b) 0.3% Sb₂Se₃Sb₂Se₃cathodes at 1C between 3.0 and 4.3 V after 3 cycles of film-formation process at 0.1C. The corresponding dQ/dV profiles are shown on the right, in which three peaks are assigned to H1-M, M-H2 and H2-H3, respectively. c, d) Cycling performance of the NCM90 and 0.3% Sb2Se3 electrodes operated at 30 oC in the voltage range of 3.0~4.3 V and the corresponding average voltage during cycling. e) Cycling performance at high discharge rate (1000 mA g^-1). f) Rate performance at 30 oC. g) Fitting results (R_e, R_sf, R_ct) based on Nyquist plots for NCM90 and 0.3% Sb₂Se₃during cycling. h) Leakage current tests fixed at 4.3 V for NCM90 and 0.3% Sb₂Se₃ electrodes.

要点三：Sb₂Se₃改性对NCM90正极首圈结构变化的影响：提升了材料的结构稳定性

Figure 3. a) In situ XRD patterns of NCM90 (green color) and 0.3% Sb₂Se₃ (blue color) electrodes. Present on the right are the magnified dQ/dV profiles at H2-H3 peak and the evolution of unit cells parameters c and V during cycling. In situ Ni K-edge XANES spectra and the corresponding k2 weighted EXAFS spectra of b) NCM90 and c) 0.3% Sb₂Se₃ electrodes during first charging process. The soft XAS spectra of d) O K-edge and e) Ni L-edge spectra at full charged state (4.3 V) for NCM90 and Sb₂Se₃-modified electrodes. f) the XANES spectra of Ni K-edge for two electrodes charged to 4.3 V and the corresponding 1st derivative. g) Ni K-edge Fourier-transformed EXFAS spectra and the fitted data of NCM90 andSb₂Se₃modified electrodes.

要点四：Sb₂Se₃改性对NCM90正极循环后颗粒形貌以及界面结构演变的影响：抑制循环过程中的颗粒破碎以及缓解了界面处层状结构向盐岩相的转变

Figure 4. a) SEM images and b) TEM images for a) NCM90 and b) Sb₂Se₃electrodes after 100 cycles. c) The soft XAS spectra of O K-edge for NCM90 and Sb₂Se₃modified electrodes after 100 cycles. The soft XAS spectra of Ni L-edge with different etching depths (0, 10, 20, 30 nm) for d) NCM90 and e)Sb₂Se₃-modified electrodes after 100 cycles. f) XANES spectra comparison of Ni K-edge for pristine and cycled electrodes and NiO as a standard represents Ni2+

要点五：Sb₂Se₃改性对NCM90 正极界面演变的影响：抑制高镍正极表面常见的EC脱氢反应，减少了表面副产物的累积

Figure 5. DRIFT spectra of a) C=O stretching and b) P-F stretching acquired from fresh electrolyte (black color), the full-charged NCM90 (green color) and 0.3% Sb₂Se₃ (blue color) electrodes with electrolyte attached. The difference spectra are shown on the top, called as D-NCM90 (light green color) and D-Sb₂Se₃ (light blue color). DFT simulated spectra of solvents EC/DEC and their different states (dehydrogenation, coordinated with Li+, Li+ coordinated with dehydrogenation solvents) are exhibited on the right. XPS spectra of c) C 1s, d) O 1s, e) Ni 2p for NCM90 and 0.3% Sb₂Se₃ electrodes after 100 cycles. TOF-SIMS measurements for f) NCM90 and g) 0.3% Sb₂Se₃ electrodes after 100 cycles. h) The selected fragments (C2HO^-, C2H3O^-, PO3-, NiF3^-, LiF2^-) distribution on NCM90 and 0.3% Sb₂Se₃electrodes after 100 cycles.

感谢合肥国家同步辐射实验室XMCD线站和中国散裂中子源提供的中子粉末衍射测试支持；感谢安徽创谱仪器科技有限公司台式XAFS谱仪（Table XAFS-500）提供了原位电化学X射线吸收谱测试支持。

“Enabling the strengthened structural and interfacial stability of high-nickel LiNi_0.9Co_0.05Mn_0.05O₂ cathode by a coating-doping-microstructure regulation three-in-one strategy”

https://doi.org/10.1002/adfm.202406068

乔羽，教授、博士生导师，厦门大学化学化工学院 / 固体表面物理化学国家重点实验室，中国福建能源材料科学与技术创新实验室（嘉庚创新实验室）。研究内容：二次电池相关新型储能体系（富锂、高镍等高电压正极材料中阴离子氧化还原机理，电极电解液表界面电化学过程及相关溶剂化构型改性研究，二次电池产气精细分析等）；电化学原位谱学表征（电化学原位气相质谱色谱联用、Raman、红外等）。学术成果：以第一作者和通讯作者身份在Nature Energy (2篇), Nature Catalysis, Nature Sustainability, Joule (7篇), J. Am. Chem. Soc. (3篇), Angew. Chem. (7篇), Adv. Mater. (10篇),等科研期刊发表学术论文50余篇。获奖情况：国家海外高层次青年引进人才计划、福建省杰青、闽江特聘教授等。

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