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Visualization of Electrode-Electrolyte Interfaces in LiPF6/EC/DEC Electrolyte for Lithium Ion Batteries via In-Situ TEM

Multimetallic nanoframes with 3D surfaces image
A: An illustration for home-made TEM holder and micro-fabricated electrochemical liquid cell. B: Real-time imaging of SEI formation. C: lithiated layer deposition and dendritic growth.

Scientific Achievement
Via in-situ electrochemical liquid cell transmission electron microscope (TEM), electrochemical reaction dynamics at the electrolyte-electrode interfaces are visualized in commercial electrolyte for lithium ion batteries.

Significance and Impact
The development of electrochemical-liquid cell visualization method sheds lights on strategies of addressing batteries failures, improving batteries design and also enabling the next-generation energy storage systems.

Summary
Lithium metal is the lightest and most electropositive of metals, making it the ideal anode material. And while rechargeable lithium-ion batteries fuel our high-tech lifestyle of smartphones and gadgets, they also tend to overheat and lose their ability to hold charge over time. A battery works by transferring charge from one electrode to another via an intermediate electrolyte, and more detailed understanding of the electrochemical reaction dynamics at electrolyte-electrode interfaces is important for improving lithium battery technology.

Haimei Zheng’s team at Berkeley Lab developed an electrochemical-liquid cell visualization method, using transmission electrom microscope (TEM) to vapture electrochemical lithiation and delithiation of Au annodes in a commercial LiPF6/EC/DEC electrolyte for lithium ion batteries. Lithium metal dendritic growth and dissolution (one main known cause of failure in lithium ion batteries), electrolyte decomposition, and solid-electrolyte interface formation were observed in situ. This technique opens a venue by which to look inside the electrochemistry at unprecedented level, and thus for improving electrode design for reducing short-circuit failure and improving the performance of lithium ion batteries.

Z. Zeng, W.I. Liang, H.-G. Liao, H. Xin, Y.-H. Chu, and H. Zheng. Visualization of electrode-electrolyte interfaces in LiPF6/EC/DEC electrolyte for lithium ion batteries via in situ TEM. Nano Lett/, 14(4), 1745-1750 (2014). DOI: 10.1021/nl403922u