华南理工大学熊训辉团队开发了苯氧自由基诱导高速无枝晶锂金属阳极双层保护膜形成的方法。相关研究成果发表在2021年9月28日出版的《德国应用化学》。

锂金属阳极的不可控枝晶生长导致循环稳定性和安全性较差，阻碍了其在高能量密度电池中的应用。

该文提出了一种苯氧基螺环-O8作为锂金属阳极的人工保护膜，因为其具有优良的成膜能力和显著的离子导电性。Spiro-O8和Li金属之间的自发氧化还原反应导致在底部形成均匀且高度离子导电的有机膜。同时，Spiro-O8表面的苯氧自由基促进了锂盐在乙醚电解液中的分解，并在顶部形成LiF膜。由于内部高离子导电膜和外部刚性膜的协同效应，在高电流密度（10 mA cm^-2下4000次循环）和5 mAh cm^-2的高面积容量下，可实现稳定的锂电镀/剥离550h，锂的超高利用率为54.6%。

作为概念证明，该研究为合理制备锂金属阳极双层界面提供了一种简便的方法。

附：英文原文

Title: Phenoxy Radical-induced Formation of Dual-Layered Protection Film for High-Rate and Dendrite-free Lithium Metal Anodes

Author: Chao Chen, Qianwen Liang, Zhongxin Chen, Weiya Zhu, Zejun Wang, Yuan Li, Xianwen Wu, Xunhui Xiong

Issue&Volume: 2021-09-28

Abstract: The uncontrollable dendrite growth of Li metal anode leads to poor cycle stability and safety concerns, hindering its utilization in high energy density batteries. Herein, a phenoxy radical Spiro-O8 is proposed as an artificial protection film for Li metal anode owing to its excellent film-forming capability and remarkable ionic conductivity. A spontaneous redox reaction between the Spiro-O8 and Li metal results in the formation of a uniform and highly ionic conductive organic film in the bottom. Meanwhile, the phenoxy radicals on surface of Spiro-O8 facilitate the decomposition of Li salt upon exposed to the ether electrolyte and lead the formation of LiF film on the top. Arising from the synergistic effects of inner high ionic conductive film and outer rigid film, stable Li plating/stripping can be realized at a high current density (4000 cycles at 10 mA cm-2) and a high areal capacity of 5 mAh cm-2  for 550 h with an ultrahigh Li utilization rate of 54.6%. As a proof of concept, this work shows a facile strategy to rationally fabricate dual-layered interfaces for Li metal anodes.

DOI: 10.1002/anie.202110441

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202110441