Solid-state Li-ion batteries with lithium anodes offer higher energy densities and are safer than conventional liquid electrolyte-based Li-ion batteries. However, the growth of lithium dendrites across the solid-state electrolyte layer leads to the premature shorting of cells and limits their practical viability. Here, using solid-state Li half-cells with metallic interlayers between a garnet-based lithium-ion conductor and lithium, we show that interfacial void growth precedes dendrite nucleation and growth. Specifically, void growth was observed at a current density of around two-thirds of the critical current density for dendrite growth. Computational calculations reveal that interlayer materials with higher critical current densities for dendrite growth also have the largest thermodynamic and kinetic barriers for lithium vacancy accumulation at their interfaces with lithium. Our results suggest that interfacial modification with suitable metallic interlayers decreases the tendency for void growth and improves dendrite growth tolerance in solid-state electrolytes, even in the absence of high stack pressures.

具有锂阳极的固态锂离子电池提供更高的能量密度，并且比传统的基于液体电解质的锂离子电池更安全。然而，锂枝晶在固态电解质层上的生长导致电池过早短路并限制了它们的实际可行性。在这里，使用在石榴石基锂离子导体和锂之间具有金属夹层的固态锂半电池，我们表明界面空隙生长先于枝晶成核和生长。具体而言，在枝晶生长临界电流密度的三分之二左右的电流密度下观察到空隙生长。计算计算表明，对于枝晶生长具有更高临界电流密度的夹层材料在其与锂的界面处也具有最大的锂空位积累的热力学和动力学势垒。我们的研究结果表明，即使在没有高堆压的情况下，使用合适的金属中间层进行界面改性也会降低固态电解质中空隙生长的趋势并提高枝晶生长的耐受性。