Long Cycling Life Solid-State Li Metal Batteries with Stress Self-Adapted Li/Garnet Interface

Inorganic solid-state electrolyte (SSE) has offered a promising option for the safe rechargeable Li metal batteries. However, the solid-solid interfacial incompatibility greatly hampers the practical use. The interface becomes even worse during repeated Li plating/stripping, especially under high current density and long cycling operation. To promise an intimate contact and uniform Li deposition during cycling, we herein demonstrate a stress self-adapted Li/Garnet interface by integrating Li foil with a hyperelastic substrate. Consecutive and conformal physical contact was ensured at Li/Garnet interface during Li plating/stripping, therefore dissipating the localized stress, suppressing Li dendrite formation, and preventing Garnet cracks. Record long cycling life over 5000 cycles was achieved with the ultrasmall hysteresis of 55 mV at high current density of 0.2 mA cm^-2. Our strategy provides a new way to stabilize Li/Garnet interface from the perspective of anode mechanical regulation and paves the way for the next generation solid-state Li metal batteries.