Reducing Interfacial Resistance between Garnet-Structured Solid-State Electrolyte and Li-Metal Anode by a Germanium Layer
Reducing Interfacial Resistance between Garnet-Structured Solid-State Electrolyte and Li-Metal Anode by a Germanium Layer
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DOI：
10.1002/adma.201606042
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发表时间：
2017-06-13
影响因子：
29.4
通讯作者：
Hu, Liangbing
中科院分区：
文献类型：
--
作者：
Luo, Wei;Gong, Yunhui;Hu, Liangbing
全固态锂电池(SSLiB)正朝着高安全性、高功率密度和高能量密度方向发展。由于具有高的锂离子导电性、宽的电势窗口和足够的热/化学稳定性，加奈特结构的固体电解质在固体锂离子电池中显示出巨大的应用前景。石榴石的一个主要挑战是，由于石榴石的刚性，石榴石与锂金属阳极之间的接触很差，导致活性中心有限，界面电阻大。本研究提出了一种通过在石榴石表面沉积一层较薄的锗(Ge)(20 Nm)来降低石榴石/锂金属界面电阻的新方法。通过这种方法，由于Li金属和Ge之间的合金化反应，石榴石/Li-金属界面的电阻从大约900降到大约115欧加厘米(2)。第一性原理计算结果与实验结果一致，证实了锂化锗层与石榴石界面具有良好的稳定性和润湿性。通过这种方式，这种独特的Ge修饰技术使金属锂、石榴石电解液和LiFePO4正极在室温下实现了稳定的循环性能。
Substantial efforts are underway to develop all-solid-state Li batteries (SSLiBs) toward high safety, high power density, and high energy density. Garnetstructured solid-state electrolyte exhibits great promise for SSLiBs owing to its high Li-ion conductivity, wide potential window, and sufficient thermal/chemical stability. A major challenge of garnet is that the contact between the garnet and the Li-metal anodes is poor due to the rigidity of the garnet, which leads to limited active sites and large interfacial resistance. This study proposes a new methodology for reducing the garnet/Li-metal interfacial resistance by depositing a thin germanium (Ge) (20 nm) layer on garnet. By applying this approach, the garnet/Li-metal interfacial resistance decreases from approximate to 900 to approximate to 115 Omega cm(2) due to an alloying reaction between the Li metal and the Ge. In agreement with experiments, first-principles calculation confirms the good stability and improved wetting at the interface between the lithiated Ge layer and garnet. In this way, this unique Ge modification technique enables a stable cycling performance of a full cell of lithium metal, garnet electrolyte, and LiFePO4 cathode at room temperature.