锂在石墨烯表面吸附稳定性的第一性原理研究

A first-principles study on the adsorption stability of lithium on graphene surfaces

  • 摘要: 基于第一性原理,深入研究了锂(Li)在石墨烯表面的吸附稳定性能. 结果显示,Li原子在石墨烯表面的最稳定吸附位点为C6环中心位(H位),吸附能为−2.80 eV. 随着Li吸附密度的增加,吸附能值逐渐变正,吸附稳定性减弱. 同时,石墨烯层间距对Li吸附也有显著影响,层间距在0.43~0.44 nm时,Li的吸附稳定性最佳. 此外,Li从一个H位点迁移到另一个H位点的迁移能垒较高(0.25 eV),印证了Li在石墨烯表面具有优异的结构稳定性. 研究从原子尺度揭示了石墨烯负极材料的储锂机制,为高性能锂离子电池的电极设计提供了理论指导.

     

    Abstract: This study delves into the adsorption stability of lithium (Li) on graphene surfaces based on first-principles calculations. The findings reveal that the most stable adsorption site for Li atoms on graphene is the center of the C6 ring (designated as the H site), with an adsorption energy of −2.80 eV. As the adsorption density of Li increases, the adsorption energy gradually shifts towards positive values, indicating a reduction in adsorption stability. Concurrently, the interlayer spacing of graphene exerts a notable influence on Li adsorption, with optimal stability observed when the spacing ranges from 0.43 to 0.44 nm. Moreover, the migration energy barrier for Li to transition from one H site to another is relatively high (0.25 eV), further confirming the exceptional structural stability of Li on the graphene surface. This research elucidates the lithium storage mechanism of graphene anode materials at the atomic level, offering theoretical insights for the electrode design of high-performance lithium-ion batteries.

     

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