Role of polymeric binders on mechanical behavior and cracking resistance of silicon composite electrodes during electrochemical cycling

JOURNAL OF POWER SOURCES

卷:387

Article

Li, Dawei^1,2  Wang, Yikai²  Hu, Jiazhi²  Lu, Bo¹  Dang, Dingying²  Zhang, Junqian^3,4,5  Cheng, Yang-Tse² 

[1] Shanghai Univ, Shanghai Inst Appl Math & Mech, Shanghai 200072, Peoples R China

[2] Univ Kentucky, Dept Chem & Mat Engn, Lexington, KY 40506 USA

[3] Shanghai Univ, Dept Mech, Shanghai 200444, Peoples R China

[4] Shanghai Key Lab Mech Energy Engn, Shanghai 200072, Peoples R China

[5] Shanghai Univ, Mat Genome Inst, Shanghai 200444, Peoples R China

关键词: Silicon;    Polymer binder;    Elastic modulus;    Stress evolution;    Cracking resistance;   

DOI  :  10.1016/j.jpowsour.2018.03.048

来源: Elsevier

【 摘 要 】

This work focuses on understanding the role of various binders, including sodium alginate (SA), Nafion, and polyvinylidene fluoride (PVDF), on the mechanical behavior and cracking resistance of silicon composite electrodes during electrochemical cycling. In situ curvature measurement of bilayer electrodes, consisting of a silicon-binder-carbon black composite layer on a copper foil, is used to determine the effects of binders on bending deformation, elastic modulus, and stress on the composite electrodes. It is found that the lithiation induced curvature and the modulus of the silicon/SA electrodes are larger than those of electrodes with Nafion and PVDF as binders. Although the modulus of Nafion is smaller than that of PVDF, the curvature and the modulus of silicon/Nafion composite are larger than those of silicon/PVDF electrodes. The moduli of all three composites decrease not only during lithiation but also during delithiation. Based on the measured stress and scanning electron microscopy observations of cracking in the composite electrodes, we conclude that the stress required to crack the composite electrodes with SA and Nafion binders is considerably higher than that of the silicon/PVDF electrode during electrochemical cycling. Thus, the cracking resistance of silicon/SA and silicon/Nafion composite electrodes is higher than that of silicon/PVDF electrodes.

【 授权许可】

Free