Coupling electrolyte mechanical reinforcement and interfacial stress relaxation for near-ambient sulfide all-solid-state lithium metal batteries

All-solid-state lithium metal batteries offer the promise of higher energy density and improved safety compared with conventional lithium-ion batteries; however, their practical operation at room temperature and low stack pressures ( ~ 0.1 MPa) remains challenging due to lithium dendrite formation and stress-induced interfacial degradation. Herein, we demonstrate near-ambient operation ( ≤ 0.3 MPa, room temperature) of all-solid-state lithium metal batteries through a combined electrolyte–current collector design. A self-polymerizable thioctic acid-modified composite solid electrolyte suppresses internal lithium metal creep with high stress tolerance, while a porous carbon matrix current collector provides localized stress relaxation and accommodates lithium deposition within internal voids. As a result, stable long-term cycling is achieved under near-ambient conditions even at a high areal loading of 2.4 mAh cm−2 using a LiNi0.8Co0.1Mn0.1O2 positive electrode operated at 0.1 C. These findings highlight the importance of controlling lithium deformation and stress relaxation for the development of practical all-solid-state lithium metal batteries. All-solid-state lithium metal batteries can suffer from dendrite growth and interfacial stress at low pressures. Here, authors couple a self-polymerizable composite sulfide electrolyte with a porous carbon current collector, enabling stable near-ambient condition cycling at high areal loading.