Temperature dependent flux balance of the Li/Li7La3Zr2O12 interface
Temperature dependent flux balance of the Li/Li7La3Zr2O12 interface
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DOI：
10.1016/j.electacta.2018.11.034
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发表时间：
2019-02
影响因子：
6.6
通讯作者：
Michael J. Wang;J. Wolfenstine;J. Sakamoto
中科院分区：
文献类型：
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作者：
Michael J. Wang;J. Wolfenstine;J. Sakamoto
安全、高能量密度锂离子电池的潜力推动了固体电解质Li7La3Zr2O12(LLZO)的发展，以物理稳定锂-电解液界面。虽然致密的LLZO是一种相对较硬的陶瓷，但已经观察到，在一定的临界电流密度(Ccd)以上，Li金属仍然可以通过多晶和单晶LLZO传播。然而，报告的CCD值仍然远低于与电动汽车等应用相关的当前密度制度(≥3 Ma cm−2)。使用最近开发的方法研究了电荷耦合器件与温度之间的关系，这种方法可以在没有界面涂层的情况下实现持续的低界面阻抗，这可能会使控制界面稳定性的因素的分析复杂化。通过对Li-电解液界面Li+离子通量的分析，推测Li在Li电极中的固相扩散系数可能是控制电荷耦合器件的一种控制机制。这些结果表明，在室温下达到∼1 mA cm−2和在100 °C下达到 7 mA cm−2时，LLZO的无枝晶循环得到了改善，而不需要涂层来实现低界面电阻(∼10 Ω cm2)。此外，本文的分析还可能为锂的扩散系数在通过陶瓷电解液的锂传播中的作用提供更多的见解。
The potential for safe, high energy-density Li-ion batteries has motivated the development of the solid electrolyte Li7La3Zr2O12(LLZO) to physically stabilize the Li-electrolyte interface. Although dense LLZO is a relatively hard ceramic, it has been observed that above a certain critical current density (CCD), Li metal can still propagate through both polycrystalline and single crystalline LLZO. However, reported values of CCD are still well below the current density regimes relevant to applications like electric vehicles (≥3 mA cm−2). The relationship between CCD and temperature was studied using recently developed methods for achieving consistently low interfacial impedances without interfacial coatings that can complicate the analysis of what controls interface stability. By analyzing the flux of Li+ions at the Li-electrolyte interface, it is hypothesized here that solid-state diffusivity of Li in the Li electrode may be a governing mechanism that controls the CCD. These results demonstrate an improvement for dendrite-free cycling in LLZO up to ∼1 mA cm−2at room temperature and ∼7 mA cm−2at 100 °C without the need for coatings to achieve low interface resistances (∼10 Ω cm2). Furthermore, the presented analysis may provide additional insight on the role of Li diffusivity in Li propagation through ceramic electrolytes.