A first-principles study of NbSe2 monolayer as anode materials for rechargeable lithium-ion and sodium-ion batteries
A first-principles study of NbSe2 monolayer as anode materials for rechargeable lithium-ion and sodium-ion batteries
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NbSe2单层作为可充电锂离子和钠离子电池负极材料的第一性原理研究
DOI：
10.1088/1361-6463/aa6eca
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发表时间：
2017-06-14
影响因子：
3.4
通讯作者：
Dai, Ying
中科院分区：
文献类型：
--
作者：
Lv, Xingshuai;Wei, Wei;Dai, Ying
人们非常希望寻找具有良好性能的可再充电金属离子电池的合适阳极，其不仅需要大容量，而且需要优异的倍率性能和循环稳定性。在这项工作中，NbSe 2单分子层的电子性质进行了探索基于第一性原理计算。我们进行了一个完整的几何优化的Li/Na-吸附结构，并获得了有利的吸附位。原始NbSe 2单层和Li/Na吸附的NbSe 2的金属特性确保了良好的导电性。此外，我们还发现NbSe 2单分子膜在富Li/Na条件下更倾向于吸附Li和Na原子，且吸附能较小，表明NbSe 2单分子膜作为电极的优越性。然后，我们获得了Li的约0.205eV的相对低的扩散势垒，特别是Na的约0.086eV的显著小的扩散势垒，这确保了NbSe 2单层作为电池电极的优异循环性能。最重要的是，NbSe 2单层中的Li和Na吸附密度可以与Li 2NbSe 2和Na 4 NbSe 2一样高，分别对应于203和312 mAh.g（-1）的理论比容量。并预测了Li_2NbSe_2和Na_4NbSe_2的平均电极电位分别为0.51 V和0.22 V。鉴于这些优异的性能，我们的工作预测，NbSe 2单分子膜可以是一个有前途的负极材料的低成本高性能的锂离子和钠离子电池的发展。
There is a great desire to search for suitable anodes with good performance for rechargeable metal-ion batteries, which require not only large capacity but excellent rate performance and cycling stability. In this work, the electronic properties of NbSe2 monolayer were explored based on first-principles calculations. We performed a full geometry optimization for Li/Na-adsorbed structures and obtained favorable adsorption sites. The metallic character for both pristine NbSe2 monolayer and the Li/Na-adsorbed NbSe2 ensures good electrical conduction. In addition, we find that NbSe2 monolayer is more inclined to adsorb Li and Na atoms with smaller adsorption energy under Li/Na-rich condition, indicating the superiority of NbSe2 monolayer as an electrode. Then, we obtained a relatively low diffusion barrier of approximately 0.205 eV for Li and, in particular, a significantly small diffusion barrier of about 0.086 eV for Na, which ensures excellent cycling performance of NbSe2 monolayer as a battery electrode. Most importantly, the Li and Na adsorption density in NbSe2 monolayer can be as high as Li2NbSe2 and Na4NbSe2, corresponding to theoretical specific capacities of 203 and 312 mAh.g(-1), respectively. And the average electrode potentials were predicted to be 0.51 V for the chemical stoichiometry of Li2NbSe2 and 0.22 V for Na4NbSe2. In view of these excellent properties, our work predicts that NbSe2 monolayer can be a promising anode material for the development of low-cost high-performance Li-and Na-ion batteries.