Single-crystal orientation lithium for ultra-stable all-solid-state batteries

All-solid-state lithium (Li) metal batteries (ASLMBs), particularly with inorganic solid electrolytes, possess both high energy density and high safety. However, their practical application is still being severely impeded by Li dendrite formation as a fundamental but unclear issue. Here, we reveal that the anisotropic exfoliation of polycrystal Li metal due to different energies required for Li atom stripping from various Li crystal planes leads to the formation of voids upon cycling, which is the intrinsic cause for the formation of Li dendrites and interfacial cracks. We thereafter precisely tune the polycrystal Li metal to <110>-oriented single-crystal Li metal using a lattice-matching template of Li₂Ga (131) interface. During the stripping process of <110>-oriented single-crystal Li, the unstripped surface Li atoms at the Li (110) plane present lower stripping energy than those of the fresh layers, which ensures layer-by-layer Li stripping/plating and avoids Li void formation to fundamentally suppress the Li dendrite generation during long cycling. The ASLMBs using <110>-oriented single-crystal Li have ultralong stability of over 10 000 cycles at 25°C. Our results establish that regulating the crystal orientation of Li metal is a basic and practical solution for solving the dendrite formation problem and pushing forward the final real applications of ASLMBs.