二维黑磷作为锂离子电池负极材料的理论研究

Low-dimensional materials have attracted a great deal of attention lately due to their tremendous potential for wide variety of applications, for example, as photonics, magnetic，catalytic and electrode materials. Very recently, a new 2D material, layered black phosphorus or phosphorene, has been isolated in the laboratory through mechanical exfoliation form bulk black phosphorus. This new member in the 2D-material family has immediately brought about intensive research interest, particularly in electrode application. To achieve this goal, many basic scientific issues must be addressed before technique applications, e.g., limited storage capacity of lithium ion on phosphorene, the effect of surface defects and boundary on the storage and diffusion of lithium ion, among others. On the basis of our previous study of geometry structure and bandgap engineering of low dimensional black phosphorus, we propose to investigate the effect of various factors, including layer number, doping, defect, and strain, on the performance of adsorption and diffusion of lithium ion on phosphorene using the first-principle calculations combined with molecular dynamic simulations. New insights gained from this fundament study will benefit the design of phosphorene-based electrodes with improved the storage capacity of lithium ion. We will also perform a systematic study of the adsorption and diffusion of sodium and potassium ions on the surface of phosphorene in order to reveal variation rule of the adsorption and diffusion behavior of the alkali metal ions. The variation rule attained can serve as useful guidelines for better design of novel ion battery anode materials.

低维纳米材料在光电子、磁性、催化和电极材料等方面有广泛的应用前景。最近，层状黑磷的成功剥离燃起了人们对二维黑磷作为电极材料的研究兴趣，但其中还有很多基础的科学问题尚待进一步研究，如锂离子在二维黑磷中的存储容量有限，表面缺陷和边界效应对锂离子存储和扩散的影响等。本项目基于申请者前期对低维黑磷几何结构及电子结构调制的研究成果，结合第一性原理和分子动力学计算方法，重点研究层数、掺杂、缺陷和应力等因素对锂离子在二维黑磷表面吸附及扩散行为的影响，寻找提高锂离子在二维黑磷中存储容量的调控方法；并进一步研究钠、钾离子在二维黑磷表面的吸附及扩散情况，揭示碱金属离子在二维黑磷表面的吸附和扩散行为随离子半径增加的变化规律。本项目从原子尺度系统研究碱金属离子在二维黑磷表面的吸附及扩散规律，为实验上实现高性能的新型负极材料提供理论指导。

本项目围绕维磷烯作为锂离子电池负极材料的应用以及类磷烯二维材料的结构和物性开展了系统的研究，得到了一些有意义的研究结果，主要内容包括：1）我们研究了在磷烯中碳原子掺杂对锂离子吸附及扩散性能的影响，以及锂离子在磷烯/石墨烯异质结构中的扩散情况。同时我们还预测了新型二维结构SiP作为潜在的锂离子电池负极材料的应用。2）我们从理论上预测了一种新型的二维类磷烯材料CaP3，发现其具有很好的稳定性，并且可从其体相剥离，单层的迁移率高达约20000 cm2 V-1 s-1， 并具有约1.15 eV的直接带隙。光学吸收谱的计算表明，该材料具有良好的光学性质，在电子和光学材料方面具有潜在的应用价值。3）由于磷烯在空气中易被氧化，极大阻碍了其应用，我们的计算证实了卤化的多孔磷烯(如P3Cl2)具有极好的抗氧化性，并且能保持原有的高迁移率。4）实验研究表明三元层状化合物Cu2MoS4在室温下具有铁磁性，我们通过理论计算揭示了其铁磁性的来源机理。5）通过第一性原理计算，我们系统性地研究了不同类型的线缺陷对ZnO纳米带和单层ZnO的电子和磁性的影响。6）我们合作研究了不同堆积角度的MoS2/MX2（M = Mo，Cr，W; X = S，Se）异质双层的相互作用以及电子性质，并且得到了一些普遍性的规律。