In Situ Construction of a LiF-Enriched Interface for Stable All-Solid-State Batteries and its Origin Revealed by Cryo-TEM
In Situ Construction of a LiF-Enriched Interface for Stable All-Solid-State Batteries and its Origin Revealed by Cryo-TEM
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DOI：
10.1002/adma.202000223
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发表时间：
2020-08-01
影响因子：
29.4
通讯作者：
Tao, Xinyong
中科院分区：
文献类型：
--
作者：
Sheng, Ouwei;Zheng, Jianhui;Tao, Xinyong
尽管固体聚合物电解质（SPE）具有安全性、灵活性和可加工性等优点，但其应用仍然固有地受到不稳定的锂（Li）/电解质界面的限制。本文中，通过引入Li 2S添加剂来改性Li/电解质界面以获得稳定的全固态锂金属电池（LMB）。低温透射电子显微镜（cryo-TEM）结果表明，聚环氧乙烷（PEO）电解质和锂金属阳极之间存在镶嵌界面，其中大量的Li、Li 2 O、LiOH和Li（2）CO（3）晶粒随机分布。此外，低温透射电镜观察结合分子动力学模拟表明，Li 2S的引入加速了N（CF 3SO 2）（2）（-）的分解，从而促进了Li/PEO界面处大量LiF纳米晶的形成。进一步证实生成的LiF抑制了聚合物链中C-O键的断裂，阻止了Li与PEO之间的连续界面反应。因此，具有富含LiF的界面的全固态LMB在电池配置中表现出改善的循环能力和稳定性，具有超过1800小时的超长寿命。该工作为高性能全固态LMB的合理设计开辟了一条新的途径。
The application of solid polymer electrolytes (SPEs) is still inherently limited by the unstable lithium (Li)/electrolyte interface, despite the advantages of security, flexibility, and workability of SPEs. Herein, the Li/electrolyte interface is modified by introducing Li2S additive to harvest stable all-solid-state lithium metal batteries (LMBs). Cryo-transmission electron microscopy (cryo-TEM) results demonstrate a mosaic interface between poly(ethylene oxide) (PEO) electrolytes and Li metal anodes, in which abundant crystalline grains of Li, Li2O, LiOH, and Li(2)CO(3)are randomly distributed. Besides, cryo-TEM visualization, combined with molecular dynamics simulations, reveals that the introduction of Li2S accelerates the decomposition of N(CF3SO2)(2)(-)and consequently promotes the formation of abundant LiF nanocrystals in the Li/PEO interface. The generated LiF is further verified to inhibit the breakage of C-O bonds in the polymer chains and prevents the continuous interface reaction between Li and PEO. Therefore, the all-solid-state LMBs with the LiF-enriched interface exhibit improved cycling capability and stability in a cell configuration with an ultralong lifespan over 1800 h. This work is believed to open up a new avenue for rational design of high-performance all-solid-state LMBs.