Inhibiting Dendrites by Uniformizing Microstructure of Superionic Lithium Argyrodites for All‐Solid‐State Lithium Metal Batteries

AbstractThe all‐solid‐state lithium metal battery is considered the next‐generation energy storage device with the potential to double the energy density of state‐of‐the‐art Li‐ion batteries and eliminate safety hazards. Achieving stable Li plating/stripping without dendrite propagation within the solid electrolyte is crucial for delivering the promised high energy density. In this study, through the comparison of various synthesis routes, a novel cube‐shaped microstructure in the Li5.3PS4.3ClBr0.7 argyrodite electrolyte, synthesized using the high‐speed mechanical milling followed by annealing method (BMAN‐LPSCB) is identified. The uniform microstructure allows for the production of an electrolyte pellet with significantly reduced porosity through cold pressing. The removal of defects has significantly enhanced the electrolyte's ability to inhibit dendrite formation, with a critical current density reaching 3.8 mA cm−2. The lithium symmetric cell with BMAN‐LPSCB electrolyte exhibits stable Li plating/stripping for over 150 h at a high current density and cutoff capacity of 3 mA cm−2 / 3 mAh cm−2. The all‐solid‐state Li/NCM battery utilizing the BMAN‐LPSCB electrolyte also demonstrates excellent durability, with a capacity retention of 96% over 1000 cycles at a 1C rate. This study emphasizes that the microstructure of the sulfide electrolyte is a critical factor influencing mechanically‐driven Li dendrite propagation in all‐solid‐state batteries.