LiAl二元合金体系中空位形成能的EAM计算
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摘要
采用嵌入原子法(embedded-atom method, EAM)计算了LiAl化合物中Li空位和Al空位在LiAl合金体系中的形成能.该计算是在该类合金系统中原子空位与其周围晶格中的原子发生了相互间的弛豫作用的条件下进行的.计算结果显示,和Al原子相比,Li原子更容易脱出晶格而失去,失去Li原子对晶格的结构、能量及稳定性影响较小,Li空位的形成会导致该类合金材料体积的缩小,这就保证了此类材料在充放电过程中负极的膨胀率更低,充放电过程中体积变化较小,不会造成电池鼓包,适合作为锂电池的负极部位,与实验的观察结果相符,为用于锂电池领域的LiAl合金体系物化性质的进一步研究及可能的潜在应用,提供了理论指导.
Vacancy formation energies of Li and Al atoms in the LiAl alloy systems were calculated by the embedded-atom method(EAM). The calculation was carried out under the condition that vacancies in the alloy system would relax with atoms nearby. The calculation results show that lithium ion is more easily removed from the lattice than aluminium atom, and the loss of lithium ion has less effect on the structure, energy and stability of the lattice. The formation of lithium ion vacancies will lead to the reduction of the volume of this kind of alloy material, which ensures that the expansion rate of the negative electrode is lower in the charging and discharging process, and the volume change is smaller in the charging and discharging process. It will result in battery bulging, which is suitable for the negative electrode of lithium-ion batteries. It is consistent with the experimental results. It provides a very meaningful theoretical guidance for the further study of physicochemical properties and potential applications of LiAl alloy system in the field of lithium-ion batteries.
Vacancy formation energies of Li and Al atoms in the LiAl alloy systems were calculated by the embedded-atom method(EAM). The calculation was carried out under the condition that vacancies in the alloy system would relax with atoms nearby. The calculation results show that lithium ion is more easily removed from the lattice than aluminium atom, and the loss of lithium ion has less effect on the structure, energy and stability of the lattice. The formation of lithium ion vacancies will lead to the reduction of the volume of this kind of alloy material, which ensures that the expansion rate of the negative electrode is lower in the charging and discharging process, and the volume change is smaller in the charging and discharging process. It will result in battery bulging, which is suitable for the negative electrode of lithium-ion batteries. It is consistent with the experimental results. It provides a very meaningful theoretical guidance for the further study of physicochemical properties and potential applications of LiAl alloy system in the field of lithium-ion batteries.
引文
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[2] 吴宇平,万春荣,姜长印,等.金属锂二次电池的研究进展[J].功能材料,2000,31(5):449-451.WU Y P,WAN C R,JIANG C Y,et al.Research progress on lithium metal secondary batteries[J].Journal of functional materials,2000,31(5):449-451.
[3] 陈律,文韬.B32-LiAl点缺陷结构的第一原理计算[J].信阳师范学院学报(自然科学版),2009,22(1):43-46.CHEN L,WEN T.Study on point defective structures of B32-LiAl intermetallic compound by first-principles methods[J].Journal of Xinyang Normal University (natural science edition),2009,22(1):43-46.
[4] 黄杨程.嵌入原子方法对典型金属物性的预测[D].长沙:湖南大学,2002.HUANG Y C.Prediction of physical properties of typical metals by embedded atomic method[D].Changsha:Hunan University,2002.
[5] 高鹭远.碳纳米管内嵌多种碳分子的密度泛函计算分析[J].沈阳大学学报(自然科版),2016,28(1):6-10.GAO L Y.Some calculations results of density function on encapsulation of various carbon molecules in carbon nanotubes[J].Journal of Shenyang University(natural science),2016,28(1):6-10.
[6] 陈大伟,斯小琴.一维热传导过程的计算模拟[J].沈阳大学学报(自然科学版),2018,30(4):338-341.CHEN DW,SI X Q.Computer simulation of one-dimensional heat conduction process[J].Journal of Shenyang University(natural science),2018,30(4):338-341.
[7] BELASHCHENKO D K.Electron contribution to energy of alkali metals in the scheme of an embedded atom model[J].High temperature,2012,50(3):331-339.
[8] JOHNSON R A.Alloy models with the embedded-atom method[J].Physical review B condensed matter,1989,39(17):12554-12559.
[9] GUO X Q,PODLOUCKY R,FREEMAN A J.Structural and electronic structural properties of ordered LiAl compounds[J].Physical review B condensed matter,1989,40(5):2793-2800.
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