孔状皱纹多层石墨烯支架均匀的锂离子通量,实现高性能锂金属阳极

B站影视 欧美电影 2025-10-15 16:52 1

摘要:锂金属负极(LMA)的实际应用受限于无法控制的枝晶生长,其主要成因在于循环过程中锂离子通量分布不均及体积变化显著。为克服这些挑战,本文,韩国汉阳大学Won Cheol Yoo等研究人员在《Journal of Energy Chemistry》期刊发表名为“H

1成果简介

锂金属负极(LMA)的实际应用受限于无法控制的枝晶生长,其主要成因在于循环过程中锂离子通量分布不均及体积变化显著。为克服这些挑战,本文,韩国汉阳大学Won Cheol Yoo等研究人员在《Journal of Energy Chemistry》期刊发表名为“Holey wrinkled-multilayered graphene scaffolds for uniform Li-ion flux enabling high-performance lithium metal anodes”的论文,研究提出无粘结剂的孔状皱纹多层石墨烯(HWMG)支架,用于制备具有长循环寿命的高性能锂金属负极

在高浓度氧化石墨烯(GO)悬浮液中,多孔氧化石墨烯(HGO)片层经重叠堆叠形成类粒状的多孔皱纹多层氧化石墨烯(HWMGO)。干燥过程中,少层HGO片层迅速稳定并形成褶皱,经还原后转化为HWMG。HWMG凭借边缘功能基团的化学作用展现出优异附着力。其颗粒状形态具有大量纳米孔道和高孔隙率,赋予卓越的机械柔韧性与低曲折度,从而实现均匀的锂离子通量、缓冲体积膨胀并抑制枝晶生长。因此,HWMG支架实现了超过800次循环的优异长期稳定性,以及6000小时内约7mV的电压滞后。在全电池配置中,经过350次循环后,其在0.3C条件下展现出3.34mAh cm-2的高面积容量。本研究通过提供可抑制树枝状晶体并延长循环寿命的可扩展支架设计,推动了LMA材料的实际应用。

2图文导读

图1. Material characterizations of hosts with different morphologies. Schematic illustration for HWMGO and WMGO formation (a). TEM images of HGO_8h (b) and HGO_16h (c). XRD patterns of MGO, WMGO, HWMGO_8h, and HWMGO_16h (d). TEM images of MGO (e) and HWMGO_8h (f). SEM image of HWMGO_8h (g). Photograph of the HWMG electrode without the binder (h). XPS results for O 1s of HWMGO, HWMGO-Cu, HWMG, and HWMG-Cu (i). BJH profiles of HWMGO, WMGO, and MGO (j). Inset in (j): nitrogen sorption isotherms of HWMGO, WMGO, and MGO. Electrical conductivity results of various electrodes measured using the 4-probe technique (k).

图2. Tortuosity of electrodes. Schematic illustration for tortuosity and binder effect in MG, WMG, and HWMG electrodes (a). EIS results for tortuosity calculation for binder-free HWMG, WMG, and WMG_×2 (b) and binder-contained WMG_5%, WMG_10%, and MG electrodes (c). Inset in (b and c): enlarged EIS results, respectively. Tortuosity of various electrodes measured three times using the blocking-electrolyte method, with values shown as averages (d). Simulated Li-ion transport distribution and deposition behavior influenced by scaffold tortuosity of MG (e), WMG (f), and HWMG (g). Streamlines indicate Li-ion flux, background color represents Li-ion concentration, and the black region shows deposited Li morphology.

图3. Electrochemical performances of half-cells. CE performance of HWMG, WMG, WMG_10%, MG, and Cu foil at 0.5 mA cm−2 and 1.0 mAh cm−2 (a) and at 2.0 mA cm−2 and 4.0 mAh cm−2 (b). CE performance of HWMG, WMG, and MG electrodes at 1.0 mA cm−2 (c), 2.0 mA cm−2 (d), and 3.0 mA cm−2 (e) and 1.0 mAh cm−2. CE performance comparison of HWMG electrode with host materials for LMAs (f). Overpotential of Li@HWMG, Li@WMG, and Li@MG electrodes at 0.5 mA cm−2 and 1.0 mAh cm−2 (g) and at 2.0 mA cm−2 and 4.0 mAh cm−2 (h). Overpotential of Li@HWMG, Li@WMG, and Li@MG electrodes at 2.0 mA cm−2 (i), 3.0 mA cm−2 (j), and 5.0 mA cm−2 (k) and 1.0 mAh cm−2. Overpotential and long-term stability comparison of HWMG electrode with host materials for LMAs (l).

图4. Electrochemical performances of full-cells. Rate performance of Li@HWMG||LFP, Li@WMG||LFP, and Li@MG||LFP full cells (a). Cycle performance of Li@HWMG||LFP, Li@WMG||LFP, and Li@MG||LFP full cells at 1 C (b) and 0.3 C (c). Areal capacity comparison at the 200th, 300th, 500th, and 700th cycle of Li@HWMG||LFP full cells with host materials for LMAs using ether electrolyte (d).

图5. Tortuosity and binder effect on initial Li plating and stripping. Nucleation overpotential differences for HWMG, WMG, WMG_10%, MG, and Cu foil at a current density of 0.5 mA cm−2 (a). Nucleation onset time (b) and overpotential comparison (c) for HWMG, WMG, WMG_10%, and MG at different current densities. Cross-sectional SEM images of HWMG (d), WMG (e), and MG electrodes (f) after the first Li plating at 0.5 mA cm−2 and 1.0 mAh cm−2. Cross-sectional SEM images of HWMG (g), WMG (h), and MG electrodes (i) in the initial state. Cross-sectional SEM images of HWMG (j), WMG (k), and MG electrodes (l) after the first Li plating at 0.5 mA cm−2 and 2.0 mAh cm−2. Cross-sectional SEM images of HWMG (m), WMG (n), and MG electrodes (o) after the first Li stripping at 0.5 mA cm−2 and 2.0 mAh cm−2.

图6. Tortuosity and binder effects on various stages of cycling. EIS results of the asymmetric cell test for HWMG, WMG, and MG electrodes at 0.5 mA cm−2 and 1.0 mAh cm−2 after 100 cycles at the Li stripping stage, with the overall plots (a) and a magnified section (b). Cross-sectional SEM images after Li stripping at 0.5 mA cm−2 and 1.0 mAh cm−2 for the asymmetric cell test after 10 cycles and 100 cycles for HWMG (c) and MG electrodes (d). Top view SEM images of after Li stripping at 0.5 mA cm−2 and 1.0 mAh cm−2 for the asymmetric cell test after 10 cycles for HWMG (e) and MG electrodes (h), and after 100 cycles for HWMG (f), enlarged HWMG (g), MG (i), and enlarged MG electrodes (j). GITT voltage profiles of HWMG, WMG, and MG electrodes at 0.5 mA cm−2 and 0.5 mAh cm−2 for the 50th (k), 100th (l), and 200th (m) cycles, along with a comparison of plateau overpotential differences across various cycles (n).

3小结

综上所述,将HWMG作为无粘结剂宿主材料应用于锂金属负极,显著提升了其电化学性能与长期稳定性。HWMG独特的物理特性——包括卓越的机械柔韧性、粘附性、高孔隙率、褶皱形态及低曲折度——使其能高效适应体积变化,实现电极内锂离子通量的均匀分布,从而抑制树枝状晶体生长并缓冲体积膨胀。无粘合剂的HWMG基体展现出卓越的电化学性能:在非对称电池测试中,800次循环后平均容量保持率达98.9%;对称电池测试中,6000小时内电压滞后仅约7mV。此外,采用LFP正极的整电池测试证实了HWMG的实用可行性:即使在高正极负载量下,经350次循环后仍保持3.34 mAh cm⁻²的面积容量(容量保持率达85.6%)。这些结果凸显了电极形态、机械柔韧性及粘合剂效应在提升LMA电极电化学性能与长期稳定性中的关键作用。HWMG支架为开发高能量密度锂离子电池提供了极具前景的解决方案,既解决了柔性金属箔的关键技术难题,又推动其在先进储能系统中的商业化进程。

文献:

来源:材料分析与应用

来源:石墨烯联盟

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