Zhang Linchao, Yang Junfeng, Jing Ke, Li Chunliu, Gao Yunxia, Wang Xianping, Fang Qianfeng
Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences (CAS), Hefei 230031, PR China.
University of Science and Technology of China (USTC), Hefei 230026, PR China.
ACS Appl Mater Interfaces. 2020 Mar 25;12(12):13836-13841. doi: 10.1021/acsami.9b21359. Epub 2020 Mar 11.
LiLaZrO (LLZO)-based ceramics are well-known as the most promising solid electrolytes for all-solid-state lithium metal batteries. However, its practical application has been significantly hindered by high Li/LLZO interfacial impedance as a result of poor interfacial contact. To solve these issues, in this work, the ZnO layer was magnetron sputter-deposited on LiLaCaZrTaO (LLCZTO) pellets. It was found that by introducing a 200 nm thick ZnO layer, the interfacial area specific resistance was sharply reduced to as low as 1% that of pristine LLCZTO; meanwhile, Li plating/stripping performance was improved significantly with a long life span of 320 h and a low polarization potential of 0.1 V, whereas a thicker ZnO layer of 600 nm can only improve the interface contact to a very limited extent because of the accumulated volume expansion induced by the in situ transformation of ZnO to the Li-Zn alloy, demonstrating the thickness-dependent beneficial effect of the ZnO layer on improving the Li/LLCZTO interfacial contact and therefore reducing the interfacial resistance. Accordingly, the evolution of the interfacial contact mode and the Li migration mechanism during the Li plating/stripping process without or with ZnO layers of different thicknesses were discussed in detail.
基于LiLaZrO（LLZO）的陶瓷作为全固态锂金属电池最有前景的固体电解质而闻名。然而，由于界面接触不良，其实际应用受到高Li/LLZO界面阻抗的显著阻碍。为了解决这些问题，在本工作中，通过磁控溅射在LiLaCaZrTaO（LLCZTO）颗粒上沉积ZnO层。结果发现，引入200nm厚的ZnO层后，界面面积比电阻急剧降低至原始LLCZTO的1%；同时，锂电镀/剥离性能显著改善，寿命长达320h，极化电位低至0.1V，而600nm厚的较厚ZnO层由于ZnO原位转变为Li-Zn合金引起的累积体积膨胀，只能在非常有限的程度上改善界面接触，这表明ZnO层对改善Li/LLCZTO界面接触从而降低界面电阻具有厚度依赖性的有益效果。因此，详细讨论了在有无不同厚度ZnO层的情况下，锂电镀/剥离过程中界面接触模式和锂迁移机制的演变。
