Toward cyclic durable core/shell nanostructure of Sn-C composite anodes for stable lithium storage by simulating its lithiation-induced internal strain

JOURNAL OF ALLOYS AND COMPOUNDS

卷:704

Article

Liu, Hui^1,2  Hu, Renzong¹  Huang, Cunke^3,4  Sun, Wei¹  Zhang, Hanyin¹  Zhu, Min¹ 

[1] South China Univ Technol, Sch Mat Sci & Engn, Guangdong Prov Key Lab Adv Energy Storage Mat, Guangzhou 510640, Guangdong, Peoples R China

[2] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China

[3] Guangxi Univ, Guangxi Coll, Nanning 530004, Peoples R China

[4] Guangxi Univ, Univ Key Lab Novel Energy Mat & Related Technol, Coll Phys Sci & Technol, Nanning 530004, Peoples R China

关键词: Lithium ion batteries;    Tin anode;    Deformation;    Whisker growth;    Structural design;   

DOI  :  10.1016/j.jallcom.2017.02.032

来源: Elsevier

【 摘 要 】

To explore the capacity fading mechanism during long-term cycling of the milled Sn-C lithium storage anodes, the structural stability of the cycled Sn-C electrodes has been investigated using internal strain distribution as indicator by simulation with different two-dimensional core/shell nanostructure models solved by Lagrangian description, combining with experimental results. It is revealed that the Sn-C composite of a double-coating structure with the smaller Sn coated by a stiff layer Li2O and embedding in graphite sustains less deformation, and has higher structural stability than the single-coating one. Due to the lithiation-induced stress and strain effect, Sn particles aggregate and the Sn whiskers grow in the cycled Sn-C electrodes that observed by SEM and TEM, which is closely related to the Sn transportation. This strain induced structural damage causes the capacity fading of Sn anodes. Based on the simulation of strain distribution induced by lithiation, the nanostructure has been designed for Sn-C electrodes of smaller Sn particles embedded in matrix with large elastic modulus and proper thickness to obtain optimized combination of capacity and cycleability. It would provide a guideline for designing material and microstructure of anodes for lithium ion batteries. (C) 2017 Elsevier B.V. All rights reserved.

【 授权许可】

Free