Chen Xue, Yuan Lixia, Li Zhen, Chen Sijing, Ji Haijin, Qin Yufei, Wu Longsheng, Shen Yue, Wang Libin, Hu Jingping, Huang Yunhui
ACS Appl Mater Interfaces. 2019 Aug 21;11(33):29830-29837. doi: 10.1021/acsami.9b07787. Epub 2019 Aug 12.
The conventional lithium-sulfur battery (LSB) undergoes a "solid-liquid-solid" cathode process during which the intermediate polysulfides dissolve into the electrolyte, leading to a serious "shuttle" reaction and significantly shortened lifespan. Here, we realize a novel "solid → solid" cathode mode for LSBs via a transplantable solid electrolyte interface (SEI). The SEI is in situ formed in a carbonate-based electrolyte with high-concentration dual-salt during the initial discharge process. The solid → solid cathode process does not involve any dissolution of the intermediates; hence, the "shuttle effect" can be totally eliminated. Furthermore, the SEI shows a high electrolyte compatibility and can be transplanted to the conventional carbonate-based/ether-based electrolytes. The sulfur/carbon composite with 65% sulfur delivers a reversible specific capacity of 1009 mA h g and negligible self-discharge. The SEI strategy can successfully break the limitation from the traditional "catholyte" electrode mechanism. Meanwhile, it provides large flexibility for designing high-loading carbon hosts and selecting an electrolyte for high-performance LSBs.
传统锂硫电池（LSB）在“固-液-固”阴极过程中，中间多硫化物会溶解到电解液中，导致严重的“穿梭”反应，显著缩短电池寿命。在此，我们通过可移植的固体电解质界面（SEI）实现了一种新型的LSB“固→固”阴极模式。该SEI在初始放电过程中于含高浓度双盐的碳酸盐基电解液中原位形成。“固→固”阴极过程不涉及任何中间体的溶解；因此，可以完全消除“穿梭效应”。此外，SEI表现出高电解液兼容性，并且可以移植到传统的碳酸盐基/醚基电解液中。含65%硫的硫/碳复合材料具有1009 mA h g的可逆比容量和可忽略不计的自放电。SEI策略能够成功突破传统“阴极电解液”电极机制的限制。同时，它为设计高负载碳载体和选择高性能LSB的电解液提供了很大的灵活性。
