电解质
硅
涂层
材料科学
阳极
电化学
法拉第效率
纳米颗粒
化学工程
氧化硅
纳米技术
电极
冶金
化学
工程类
物理化学
氮化硅
作者
Maxwell C. Schulze,Gerard M. Carroll,Trevor R. Martin,Kevin Sanchez-Rivera,Fernando Urias,Nathan R. Neale
出处
期刊:ACS applied energy materials
[American Chemical Society]
日期:2021-02-08
卷期号:4 (2): 1628-1636
被引量:20
标识
DOI:10.1021/acsaem.0c02817
摘要
Herein, we evaluate the effect of covalently attached molecular coating hydrophobicity on the surface of the silicon nanoparticle (Si NP) active anode material for Li-ion batteries. The experiments are a means to identify the interfacial properties that help minimize electrochemical side reactions during cycling. Preformed coatings on the Si NP surfaces prior to electrode fabrication mimic the ionically conducting and electronically insulating properties of the solid electrolyte interphase (SEI). Hydrophilic oligomers such as polyethylene oxide (PEO) and other related structures are commonly identified as Li+-conducting components of the SEI. Here, we study the effect of such hydrophilic PEO versus hydrophobic alkyl molecular coatings on Si NP anode electrochemical performance. We also study the effect of the PEO oligomer length and the resulting effective thickness of the interfacial coating on the electrochemical performance. We find that PEO oligomers electrochemically isolate Si NPs when the PEO coating thickness approaches the electron tunneling distance of ∼2.5 nm. Surprisingly, the thickness of the PEO-based coatings has a negligible effect on their ability to minimize electrochemical side reactions as measured by Coulombic efficiency. These results reveal how the interfacial coating on silicon anode materials should differ from an operando-formed SEI layer and discuss design strategies for an ideal interfacial active material coating based on these results.
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