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Lithium Metal Anode, how to achieve both stretchable and mechanical and mlectrochemical cycling mtability?

2018-07-02 来源:亚科官网
2 July 2018
  Recently, researchers from Stanford University prepared a stretchable lithium metal anode with stable mechanical and electrochemical properties for the first time. Related research has been published in the journal Joule entitled "Stretchable Lithium Metal Anode with Improved Mechanical and Electrochemical Cycling Stability" [1].
  The flexible wearable electronic device has greater mechanical flexibility, can adapt to different working environments to a certain extent, and satisfies the human body's deformation requirements, and has become a research hotspot in recent years. Retractable batteries are a key component of flexible electronic devices, but generally exhibit low energy densities due to the low lithium storage capacity of their commonly used electroactive substances such as lithium titanate. Lithium metal is an ideal negative electrode material, but after undergoing tensile deformation, it easily undergoes irreversible plastic deformation and further breaks, and the electrochemical performance of the lithium negative electrode is unstable. How to improve the tensile properties and cycle stability of materials at the same time is the main difficulty in the current study.
  Last year, the research team design a fully retractable battery (Adv. Energy Mater. [2]) based on a wave structure using a simple method, with all components including positive and negative electrodes, separators, and current collectors, shells, which can be stretched simultaneously and exhibit excellent energy density and cycle performance. In this study, they studied the retractable electrode material and used lithium metal as the negative electrode of the battery to achieve stretchability. They made a 150 micron diameter copper wire into a "one-dimensional" copper spring, and further coiled a "one-dimensional" copper spring into a "two-dimensional" spring in an "Archimedes" pattern. Then, the poly(ethylene-isobutylene-styrene) rubber (SEBS) solution is injected into the thread crevice of the spring, and the solvent is volatilized to dry to obtain a two-dimensional electrode of “metal-rubber” composite. By further electrodepositing lithium metal, a stretchable elastic lithium negative electrode can be obtained.
  The lithium metal negative electrode has strong mechanical impact energy and can ensure stable electrochemical reaction. After reciprocating mechanical deformation, the Coulomb efficiency attenuation is small, and the effective area of the electrode is greatly improved, the local current density is reduced, and the growth of lithium dendrites is suppressed. The preparation process is efficient and simple, and improves the tensile properties and cycle stability of the lithium metal electrode. The preparation method is expected to break through the bottleneck of the development of flexible wearable devices and promote the development of retractable lithium metal batteries.
[1] Kai Liu, Biao Kong, Wei Liu, et al. Stretchable Lithium Metal Anode with Improved Mechanical and Electrochemical Cycling Stability. Joule, 2018, DOI: 10.1016/j.joule.2018.06.003.
[2] Wei Liu, Jun Chen, Zheng Chen, et al. Stretchable Lithium-Ion Batteries Enabled by Device-Scaled Wavy Structure and Elastic-Sticky Separator. Adv. Energy Mater. 2017, 7, 1701076.
Edited by Suzhou Yacoo Science Co., Ltd.