Nanocomposite intermediate layers formed by conversion reaction of SnO2 for Li/garnet/Li cycle stability
Nanocomposite intermediate layers formed by conversion reaction of SnO2 for Li/garnet/Li cycle stability
复制标题
通过 SnO2 转化反应形成的纳米复合材料中间层，提高 Li/石榴石/Li 循环稳定性
DOI：
10.1016/j.jpowsour.2019.02.085
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发表时间：
2019-04-30
影响因子：
9.2
通讯作者：
Guo, Xiangxin
中科院分区：
文献类型：
--
作者：
Chen, Yue;He, Minghui;Guo, Xiangxin
石榴石具有较高的导电性和对锂离子的稳定性，是开发固体锂电池的理想固体电解质。但在镀锂和退锂过程中，它们都存在锂渗透石榴石的缺点，限制了它们的实际应用。在此，我们提出了一种解决这个问题的策略，通过在Li6.4La3Zr1.4Ta0.6O12颗粒的表面上涂覆SnO 2膜。通过SnO 2与Li在200 ℃下的转化反应，在Li和Li6.4La3Zr1.4Ta0.6O12电解质之间形成由交联的LixSn和Li 2 O组成的纳米复合层。这导致从疏锂性到亲锂性的转变，从而将界面电阻从1100 Ω cm（2）大大降低到25 Ω cm（2）。此外，利用抑制LixSn合金约260%的体积变化，在0.2mA cm（-2）的电流密度下循环650 h，中间层保持完整性。此外，Li/SnO 2-Li6.4La.Zr1.4Ta0.6O12-SnO 2/Li的临界电流密度可高达1.15 mA cm（-2）。作为一种概念验证，这种基于转化反应的界面改性方法为解决锂/石榴石界面问题，促进固态锂电池的发展提供了一条有效途径。
Garnets are promising solid electrolytes for developing solid state Li batteries, owing to their features of relatively high conductivity and stability against lithium metal. However, they show shortcoming of Li penetration through garnets during Li plating and stripping, which limits their practice application. Herein, we present a strategy to solve such problem by coating SnO2 films on the surfaces of the Li6.4La3Zr1.4Ta0.6O12 pellets. Through conversion reaction of SnO2 with Li at 200 degrees C, the nanocomposite layers consisting of crosslinked LixSn and Li2O are formed between the Li and the Li6.4La3Zr1.4Ta0.6O12 electrolytes. This leads to transition from lithiophobicity to lithiophilicity, thus greatly reducing interfacial resistance from 1100 Omega cm(2) to 25 Omega cm(2). Furthermore, taking advantage of suppressing volume change of LixSn alloy which is about 260%, the intermediate layers maintain integrity under the current densities of 0.2 mA cm(-2) for 650 h cycles. In addition, the critical current density of Li/SnO2-Li6.4La.Zr1.4Ta0.6O12-SnO2/Li can be as high as 1.15 mA cm(-2). As a proof-of-concept, this effective interface modification based on conversion reaction method contributes to a useful way of solving the Li/garnet interface problem and promoting the solid state Li batteries development.