Engineering Continuous Ion/Electron Channels in Mixed Ionic-Electronic Conductor for Solid-State Lithium Metal Batteries

Solid-state lithium metal batteries (SSLMBs) suffer from stress accumulation, poor interfacial stability, and lithium dendrite growth. A potential solution to these issues is the design of a three-dimensional nanotubular mixed ionic-electronic conductor (MIEC) as a lithium host, which induces lithium plating/stripping inside via Coble creep. Herein, we develop a novel MIEC comprising a mechanically robust and electrochemically stable titanium nitride (TiN) nanotube array, with an ion-conductive solid electrolyte interphase (SEI) coating on the inner surface of the TiN as a lithium host. The highly lithiophilic and robust MIEC provides consecutive ion/electron transport channels, promoting uniform lithium deposition inside the nanotubes and thereby maintaining exceptional interfacial stability during cycling. Consequently, SSLMBs employing this rationally designed MIEC host demonstrate remarkable electrochemical performance. This work provides new insights for the construction of advanced MIECs for high-performance SSLMBs.