最近江汉大学梁济元教授团队在纳米材料能源顶刊Nano Energy发文 (Cubic Carbon Cage Confinement of Bimetallic Fluoride: Dual Remedies for Cathode Expansion and Anode Dendrites in Lithium Metal Batteries) 提出了一种立方碳笼限域的铁/镍双金属氟化物复合材料（C@Fe_0.43Ni_0.57F₂），用于同时解决锂金属电池中正极体积膨胀与负极锂枝晶生长两大关键问题。通过构建N/F共掺杂的中空碳笼结构，实现了对双金属氟化物核心的有效限域，不仅缓解了转化型正极在循环过程中的体积变化和金属溶解问题，还显著提升了电子/离子传输动力学。在正极应用中，该结构表现出优异的倍率性能和长期循环稳定性；在负极应用中，氟化物核心的亲锂性与碳笼的空间限域效应协同诱导锂均匀沉积，并促进形成富LiF的稳定SEI层，从而抑制锂枝晶生长。基于此，构建的全电池在低N/P比条件下仍展现出优异的电化学性能，验证了该双功能材料在高能量密度锂金属电池中的应用潜力。

Figure 1. Syntheses and microstructure characterizations of C@Fe_0.43Ni_0.57F₂ nanocomposite. (a) The schematic demonstration of the preparation of C@Fe_0.43Ni_0.57F₂. (b) XRD Rietveld refinement.(Inset: Crystal structure of Fe_0.43Ni_0.57F₂.) (c) NPD pattern. (d) SEM image. (e) TEM and (f, g) HRTEM images, respectively. (h) HAADF-STEM EDX elemental mapping data. (i) Raman spectrum. (j) F 1s and (k) N 1s HRXPS spectra, respectively.

Figure 2. Half-cell electrochemical performance and Li⁺ storage mechanism and electrochemical kinetic studies. (a) The initial three CV profiles of C@Fe_0.43Ni_0.57F₂ at a scan rate of 0.1 mV s^-1. (b) The first three-cycle galvanostatic discharge/charge profiles. (c) Rate performance. (d) Cyclic performance at 1 C. (e) CV curves of C@Fe_0.43Ni_0.57F₂ at various scan rates. (f) The fitted b value determined from the peak current and sweep rate. (g) Capacity contribution ratio at various scan rates. (h) EIS Nyquist plots (inset: the applied equivalent circuit). (i) GITT profile. (j) The calculated Li⁺ diffusion coefficient.

Figure 3. (a) Projected density of states (PDOS) of C@Fe_0.43Ni_0.57F₂. (b) Planar‐averaged electron density difference of C@Fe_0.43Ni_0.57F₂. (c) ELF map of C@Fe_0.43Ni_0.57F₂ along a direction. (d) The comparison for diffusion energy barriers of Li⁺ in the Fe_0.43Ni_0.57F₂, NiF₂, and FeF₂ surfaces. HRXPS of the 0.1 C 100-cycled C@Fe_0.43Ni_0.57F₂ and C-Fe_0.43Ni_0.57F₂ cathodes CEI: (e) F 1s and (f) O 1s. Von-Mises stress of the Fe_0.43Ni_0.57F₂ electrode (g) with and (h) without the carbon cage at 1.0, 1.5 and 4.2 V when discharging at a 0.1 C constant current rate. (i) Illustration of the aggregation evolution of C@Fe_0.43Ni_0.57F₂ and C-Fe_0.43Ni_0.57F₂ cathodes.

Figure 4. Morphology evolution of the electrodeposited Li on different substrates: top view SEM images of (a-d) C@Fe_0.43Ni_0.57F₂ decorated Cu foil; (e-h) C cage decorated Cu foil and (i-l) bare Cu foil with Li plating amounts of 0.2, 0.5, 1 and 3 mAh cm^-2. Scheme illustration for the Li plating behaviors on (m) bare Cu foil, (n) carbon cage modified Cu foil, and (o) C@Fe_0.43Ni_0.57F₂.

Figure 5. (a) Galvanostatic cycling voltage profiles of C@Fe_0.43Ni_0.57F₂@Li, carbon cage@Li, and Cu@Li anodes in symmetric coin cells at 0.5 mA cm^-2 with a capacity of 0.5 mAh cm^-2. (b) CE measurements of different electrodes at the current density of 0.2 mA cm^-2 and Li deposition amount of 1 mAh cm^-2. (c) Li nucleation overpotential on different electrodes at 1 mA cm^-2 (inset: locally enlarged image). (d) Nyquist plots of theelectrode prepared by different electrodes (inset: the simplified equivalent circuit). (e) Tafel curves of different electrodes to evaluate their exchange current densities. (f) Optimized adsorption energiesand structures (insets) for Li on different electrodes surfaces. (g)Comparison of electrochemical properties of different electrodes.

Figure 6. HRXPS spectra for SEI study after 100 cycles from the coulomb efficiency tests C@Fe_0.43Ni_0.57F₂ modified Cu foil, carbon cage modified Cu foil and bare Cu foil surfaces. (a) F 1s spectra, (b) O 1s spectra, (c) Li 1s spectra. Raman spectra for the electrolyte on different current collectors: (d) the region from 700 to 760 cm^-1 and (e) the region from 885 to 915 cm^-1. (f) Solvation structure proportion of C@Fe_0.43Ni_0.57F₂, carbon cage and bare Cu foil electrodes obtained from Raman spectra. (g-i) Schematic illustration of Li deposition and SEI composition on the C@Fe_0.43Ni_0.57F₂, carbon shell and bare Cu foil electrodes.

Figure 7. Electrochemical performances of the full cell. (a) Schematic demonstration of the novel C@Fe_0.43Ni_0.57F₂@Li||C@Fe_0.43Ni_0.57F₂ LMB full cell configuration. (b) CV curves at a scan rate of 0.1 mV s^-1. (c) Rate performance. (d) Galvanostatic discharge/charge profiles at various current rates. (e) Cyclic performance at a constant current density of 0.2 C. (f) Comparison of full cell performance of C@Fe_0.43Ni_0.57F₂ with previously reported metal fluoride cathode materials.

【文献信息】

Du, K.; Su, B.; Li, C.; Wang, H.; Li, H.; Liu, Z.; Wang, D.; Tao, R.; Liu, J.; Liang, J., Cubic Carbon Cage Confinement of Bimetallic Fluoride: Dual Remedies for Cathode Expansion and Anode Dendrites in Lithium Metal Batteries. Nano Energy 2026,150, 111795.

文章来源：能源学人

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