Over 500 Wh kg –1 Solid-State Lithium Metal Batteries with Long Cycling Stability Using In Situ Polymerized Electrolyte

and cycles stably for 70 cycles at 4.6 V, representing the best balance between cycling performance and energy density for polymer-electrolyte-based LMBs. The high-energy-density pouch cells also demonstrate superior safety in nail-penetration tests. This work presents a promising strategy for developing practical high-energy-density and high-safety LMBs.