Phase Evolution of a Prenucleator for Fast Li Nucleation in All‐Solid‐State Lithium Batteries

Abstract Undesirable Li dendrite growth under high current densities due to the nonuniform Li nucleation and growth has significantly hindered the development of high‐rate all‐solid‐state lithium batteries (ASSLBs). Herein, the phase evolution of a Li prenucleator (MoS 2 ) is shown in working ASSLBs that renders a highly active nucleator (Mo), where Mo promotes fast Li nucleation and Li dendrite suppression. During plating, Li shows strong affinity with Mo, which guides Li fast nucleating and selectively depositing on Mo surface with a large specific surface, thus reducing the local current density. Moreover, a fast diffusion of Li atom on Mo (110) surface promotes uniform Li deposition and limits the Li dendrite growth. Benefitting from the reduced local current density as well as the improved Li dendrite suppression, Li–Li symmetric cells within MoS 2 prenucleator demonstrate excellent electrochemical performance, achieving cycle lifetimes as high as 1000 h for 1 mA cm −2 /1 mAh cm −2 and 780 h for 0.5 mA cm −2 /2 mAh cm −2 . Additionally, developed Li‐LFP ASSLBs demonstrate high capacity retention of 78% with an ultra‐long cycling life of 3000 cycles under a high current density of 1 mA cm −2 . The general concept has the potential to be extended to other metal‐sulfide prenucleators.