‘Anode-free’ or, more fittingly, metal reservoir-free cells could drastically improve current solid-state battery technology by achieving higher energy density, improving safety and simplifying manufacturing. Various strategies have been reported so far to control the morphology of electrodeposited alkali metal films to be homogeneous and dense, but until now, the microstructure of electrodeposited alkali metal is unknown, and a suitable characterization route is yet to be identified. Here we establish a reproducible protocol for characterizing the size and orientation of metal grains in differently processed lithium and sodium samples by a combination of focused ion beam and electron backscatter diffraction. Electrodeposited films at Cu|Li_6.5Ta_0.5La₃Zr_1.5O₁₂, steel|Li₆PS₅Cl and Al|Na_3.4Zr₂Si_2.4P_0.6O₁₂ interfaces were characterized. The analyses show large grain sizes (>100 µm) within these films and a preferential orientation of grain boundaries. Furthermore, metal growth and dissolution were investigated using in situ electron backscatter diffraction, showing a dynamic grain coarsening during electrodeposition and pore formation within grains during dissolution. Our methodology and results deepen the research field for the improvement of solid-state battery performance through a characterization of the alkali metal microstructure.

“无阳极”或更恰当地说，无金属储液罐电池可以通过实现更高的能量密度、提高安全性和简化制造来大幅改进当前的固态电池技术。迄今为止，已经报道了各种策略来控制电沉积碱金属膜的形貌均匀和致密，但到目前为止，电沉积碱金属的微观结构尚不清楚，尚未确定合适的表征路线。在这里，我们建立了一个可重复的方案，用于通过聚焦离子束和电子背散射衍射的组合来表征不同加工的锂和钠样品中金属晶粒的大小和取向。Electrodeposited films at Cu|Li_6.5Ta_0.5La₃Zr_1.5O₁₂，钢|Li₆PS₅Cl 和 Al|表征了 Na_3.4Zr₂Si_2.4P_0.6O₁₂ 个界面。分析显示这些薄膜内的大晶粒尺寸 （>100 μm） 和晶界的优先取向。此外，使用原位电子背散射衍射研究了金属的生长和溶解，显示了电沉积过程中动态晶粒粗化和溶解过程中晶粒内的孔隙形成。我们的方法和结果通过表征碱金属微观结构来深化提高固态电池性能的研究领域。