Garnet电解质/Li金属界面改性

通过物理/化学沉积方法在Garnet电解质(Li6.85La2.9Ca0.1Zr1.75Nb0.25O12,LLCNZO)表面沉积不同类型过渡层,在相同条件下来综合比较其对界面改性程度的差别。采用恒流充放电、电化学阻抗谱、扫描电子显微镜等方法,研究了几种代表性过渡层Al-doped ZnO(AZO),Si-Ti合金,C,Ti以及LiPON]对Garnet电解质/Li界面阻抗的影响。通过研究结果比较,当所沉积的过渡层与Li金属反应时,可以最大程度地降低界面阻抗(如AZO过渡层可以使界面阻抗由192 000Ω/cm^2降低至1 564.5Ω/cm^2)。其主要原因在于该类界面层的引入可以有效增加电极与电解质之间的接触面积,同时还可以均匀化界面电场的分布,从而提高抑制锂生长和穿透电解质片的能力,改善Garnet电解质与Li金属之间的界面性能。

Interfacial modification between Garnet-type solid-state electrolytes and Li metal

Various of transition layers were deposited on the surface of Garnet electrolyte(Li6.85La2.9Ca0.1Zr1.75Nb0.25O12,LLCNZO)by physical or chemical vapor deposition to modify the electrolyte/Li metal interface.The effects of several transition layersAl-doped ZnO(AZO),Si-Ti alloy,C,Ti and LiPON] on the interface resistance between Garnet electrolyte and Li metal were investigated by galvanostatic charge/discharge,electrochemical impedance spectroscopy and scanning electron microscopy.The results indicate that when the deposited transition layer can easily react with Li metal,the interface impedance can be minimized(for example,the AZO transition layer can reduce the interface impedance from 192 000 Ω/cm^2 to 1 564.5 Ω/cm^2).The main reason may be that the addition of these interlayers is beneficial to increase the contact area between the Li metal and the electrolyte,and at the same time even the distribution of the interfacial electric field,so as to improve the ability of inhibiting the growth of lithium and penetrating the electrolyte sheet,and improve the interface performance between the Garnet electrolyte and Li metal.