Molding of Li_5.5PS_4.5Cl_1.5 Particles Based on Regulating Li⁺ Transport for All-Solid-State Li Metal Battery

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_5.5PS_4.5Cl_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.