Lithium metal batteries using solid electrolytes are considered the next-generation lithium batteries due to their enhanced energy density and safety. However, interfacial instabilities between Li-metal and solid electrolytes limit their implementation in practical batteries. Herein, Li-metal batteries using tailored garnet-type Li7-xLa3Zr2-yO12 (LLZO) solid electrolytes are reported, which shows remarkable stability and energy density, meeting the lifespan requirements of commercial applications. We demonstrate that the compatibility between LLZO and lithium metal is crucial for long-term stability, which is accomplished by bulk dopant regulating and dopant-specific interfacial treatment using protonation/etching. An all-solid-state with 5 mAh cm-2 cathode delivers a cumulative capacity of over 4000 mAh cm-2 at 3 mA cm-2, which to the best of our knowledge, is the highest cycling parameter reported for Li-metal batteries with LLZOs. These findings are expected to promote the development of solid-state Li-metal batteries by highlighting the efficacy of the coupled bulk and interface doping of solid electrolytes.

Sewon Kim, Ju-Sik Kim, Lincoln Miara, Yan Wang, Sung-Kyun Jung, Seong Yong Park, Zhen Song, Hyungsub Kim, Michael Badding, JaeMyung Chang, Victor Roev, Gabin Yoon, Ryounghee Kim, Jung-Hwa Kim, Kyungho Yoon, Dongmin Im, Kisuk Kang