Constructing Coupled Ion‐Electron Pathways for Efficient Oxygen Chemistry in Solid‐State Lithium‐Oxygen Batteries

Abstract

ABSTRACT Solid‐state lithium‐oxygen batteries (SSLOBs) are ideal energy storage systems because of their intrinsic safety and ultrahigh theoretical energy density. However, practical implementation is severely hindered by sluggish oxygen‐redox kinetics at solid‐state air cathodes, where achieving fast ionic/electronic transport and high catalytic activity concurrently remains a formidable challenge. Here, we demonstrate a strategy to construct coupled ion‐electron pathways within a monolithic mixed ionic‐electronic catalyst (MMIEC) cathode. Using LiCoO 2 (LCO) as a model system, a seamless interface with the solid electrolyte is established via an ultrafast thermal integration process, creating continuous percolation networks for both Li + and electrons. These coupled pathways ensure unimpeded charge transport at the electrochemical interface, while surface‐enriched Co 3+ /Co 4+ redox couples act as intrinsically active catalytic centers. This architecture mediates oxygen‐redox reactions by accelerating LiO 2 * formation during discharge and promoting the reversible decomposition of Li 2 O 2 upon charge. Consequently, the MMIEC‐based SSLOB delivers an ultrahigh discharge capacity of 12970 mAh g −1 , maintains stable cycling for more than 400 cycles, and exhibits a reduced voltage polarization of 1.0 V. This work demonstrates that coupling catalytic activity with robust ionic‐electronic pathways is crucial for advancing high‐performance SSLOBs.