Abstract All‐solid‐state Li metal batteries (ASSLBs) are coming with sulfide solid‐state electrolytes (S‐SSEs) for superior Li + conductivity, but irregular particles and interfaces lead to disorder Li + flux in S‐SSEs that hinder pure Li as an anode. Specially, its mesoscopic structure cannot be adequately described by average size, making it difficult to analyze Li + flux effectively. Herein, a model is constructed on the molding of Li 5.5 PS 4.5 Cl 1.5 (LPSC) particles and defined size as the number ( N ) and consistency ( σ ) to evaluate their effects on Li + transfer and concentration uniformity. Through machine learning of calculation data (Li + concentration with N and σ ) and experimental results, excessive interfaces can hinder Li + transport and local aggregation of irregular interfaces leads to uneven ion transport. Therefore, a particle size gradient S‐SSEs (induced by different size LPSC particles) is predicted to achieve fast and uniform Li + transport. Subsequently, this designed S‐SSE is applied in ASSLBs, which can complete a 1000 h cycle with capacity retention exceeding 80%. This study elucidates that the long cycle ASSLBs can be achieved by adjusting the molding of LPSC particles. Specifically, it demonstrates that the Li + flux of the whole S‐SSEs can be optimized through gradient size design.
Li et al. (2025) studied this question.