在锂金属负极内部构建三维骨架可以抑制极片的体积变化,降低局部电流密度,延缓锂枝晶生长。本文以锂锭、无定形B粉和ZnF2粉为原材料,采用熔炼法制备内部具有三维骨架的Li-B-Zn合金。采用X射线衍射仪、扫描电子显微镜、能量色散光谱仪等表征合金的相组成及其内部骨架的结构,并对Li-B-Zn合金负极的电化学性能进行评估。结果表明：纳米LiZn颗粒均匀分布在LiB纤维骨架上,构成复合骨架,该骨架具有丰富的亲锂位点和出色的结构稳定性。在对称电池中,Li-B-Zn负极在5 mAh/cm2的高面容量下循环运行时表现出1 500 h的长循环。Li-B-Zn|LFP (LiFePO4)全电池显示出优异的电化学性能,在1 C下370次循环后,容量保持率高达90.15%。在实际应用中,Li-B-Zn合金负极具有突出的性能优势,构建内部复合三维骨架是一种解决当前锂金属负极挑战的高效方法。
Constructing a 3D skeleton inside lithium metal anodes can suppress anode volume change, reduce local current density, and retard lithium dendrite growth. In this study, Li ingots, amorphous B powder, and ZnF2 powder were used as raw materials to prepare a Li-B-Zn alloy with internal 3D skeleton via a melting method. X-ray diffractometer, scanning electron microscope, and energy dispersive spectrometer were employed to characterize the phase composition and internal skeleton structure of the alloy, while the electrochemical performance of the Li-B-Zn alloy anode was evaluated. Results show that nano-sized LiZn particles are uniformly distributed on the LiB fiber skeleton, forming a composite skeleton with abundant lithiophilic sites and excellent structural stability. In symmetric cells, the Li-B-Zn anode achieves a long cycle life of 1 500 h at a high capacity of 5 mAh/cm2. The Li-B-Zn|LFP (LiFePO4) full cell exhibits outstanding electrochemical performance, with a capacity retention rate of up to 90.15% after 370 cycles at 1 C. Li-B-Zn alloy anode has significant performance advantages in practical applications, and constructing an internal composite 3D skeleton is an efficient approach to address current challenges of lithium metal anodes.
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