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arXiv 1108.0576cond-mat.mtrl-sci
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锂在石墨碳中的扩散

Lithium Diffusion in Graphitic Carbon

Kristin Persson, Vijay A. Sethuraman, Laurence J. Hardwick, Yoyo Hinuma, Ying Shirley Meng, Anton van der Ven, Venkat Srinivasan, Robert Kostecki, Gerbrand Ceder

摘要:

石墨碳目前被认为是锂离子电池负极的最先进材料,主要是由于其高可逆性和低工作电位。然而,碳阳极表现出中等的充电/放电速率性能,这导致在长时间循环时严重的运输诱导的表面结构损伤,并限制了电池的寿命。锂在石墨碳中的体扩散尚未完全理解,部分原因是测量有限尺寸的非各向同性颗粒中的体输运性质的复杂性。为了解决这个问题的石墨,我们使用Devanathan-Stachurski电化学方法结合从头计算去卷积,并量化锂离子在高取向热解石墨(HOPG)的扩散机制。结果揭示了在平行于石墨烯平面的方向上固有的高锂离子扩散率(约100%)。10^-7 - 10^-6 cm 2 s-1),相比之下,锂离子沿晶界的缓慢传输(约为10 ^-7 - 10^-6 cm 2 s-1)。10^-11 cm ^2 s^-1),表明合理设计具有极高倍率性能的碳质材料和复合电极的可能性。

英文摘要:

Graphitic carbon is currently considered the state-of-the-art material for the negative electrode in lithium-ion cells, mainly due to its high reversibility and low operating potential. However, carbon anodes exhibit mediocre charge/discharge rate performance, which contributes to severe transport-induced surface-structural damage upon prolonged cycling, and limits the lifetime of the cell. Lithium bulk diffusion in graphitic carbon is not yet completely understood, partly due to the complexity of measuring bulk transport properties in finite-sized, non-isotropic particles. To solve this problem for graphite, we use the Devanathan-Stachurski electrochemical methodology combined with ab-initio computations to deconvolute, and quantify the mechanism of lithium-ion diffusion in highly oriented pyrolytic graphite (HOPG). The results reveal inherent high lithium-ion diffusivity in the direction parallel to the graphene plane (ca. 10^-7 - 10^-6 cm2 s-1), as compared to sluggish lithium-ion transport along grain boundaries (ca. 10^-11 cm^2 s^-1), indicating the possibility of rational design of carbonaceous materials and composite electrodes with very high rate capability.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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