In Situ Studies of Solid Electrolyte Interphase (SEI) Formation on Crystalline Carbon Surfaces by Neutron Reflectometry and Atomic Force Microscopy.
In Situ Studies of Solid Electrolyte Interphase (SEI) Formation on Crystalline Carbon Surfaces by Neutron Reflectometry and Atomic Force Microscopy.
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DOI：
10.1021/acsami.7b09181
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发表时间：
2017-10
影响因子：
9.5
通讯作者：
Miriam Steinhauer;M. Stich;M. Kurniawan;B. Seidlhofer;M. Trapp;A. Bund;N. Wagner;K. Friedrich
中科院分区：
文献类型：
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作者：
Miriam Steinhauer;M. Stich;M. Kurniawan;B. Seidlhofer;M. Trapp;A. Bund;N. Wagner;K. Friedrich
固体电解质界面（SEI）是一种复杂而脆弱的钝化层，对锂离子电池的功能至关重要。由于其易碎性和反应性，使用原位技术确定SEI形成过程中的真实结构和形态是可取的。在这项研究中，我们使用原位中子反射（NR）和原位原子力显微镜（AFM）来研究碳表面SEI的形成。研究发现，在开路电压下，碳样品表面已经存在一层富含锂的吸附层，并且第一批分解产物开始沉积在这个电位附近。在负电位扫描期间，可以通过AFM和NR详细观察SEI的生长。这可以精确监测形态演变和单个SEI特征的异质性。NR测量显示，在较低的截止电位（0.02 V vs Li/Li+）下，SEI厚度最大为192 Å，在正电位扫描期间略有下降。NR获得的散射长度密度（SLD）提供了关于SEI化学性质和结构演变的额外信息。
The solid electrolyte interphase (SEI) is a complex and fragile passivation layer with crucial importance for the functionality of lithium-ion batteries. Due to its fragility and reactivity, the use of in situ techniques is preferable for the determination of the SEI's true structure and morphology during its formation. In this study, we use in situ neutron reflectometry (NR) and in situ atomic force microscopy (AFM) to investigate the SEI formation on a carbon surface. It was found that a lithium-rich adsorption layer is already present at the open circuit voltage on the carbon sample surface and that the first decomposition products start to deposit close to this potential. During the negative potential sweep, the growth of the SEI can be observed in detail by AFM and NR. This allows precise monitoring of the morphology evolution and the resulting heterogeneities of individual SEI features. NR measurements show a maximum SEI thickness of 192 Å at the lower cutoff potential (0.02 V vs Li/Li+), which slightly decreases during the positive potential scan. The scattering length density (SLD) obtained by NR provides additional information on the SEI's chemical nature and structural evolution.