Covalent Organic Frameworks Interfacial Modification of Ceramic Electrolytes for Enhanced Electrochemical Performance

The interface instability between inorganic ceramic electrolytes and lithium metal anodes seriously affects the cycling behavior of high-performance lithium-metal batteries. Herein, an in situ interfacial modification strategy is proposed to build the precise hybrid organic/inorganic lithium-ion conducting layer where the Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) particle surface is anchored by ion-conducting covalent organic frameworks (COF) with affluent poly(ethylene glycol) (PEG) moieties. This interlayer features ion transport regulation to avoid high interfacial resistance and enhances interfacial stability by building a functional COF-based shield against electrons. These as-prepared particles are employed to fabricate flexible quasi-solid electrolyte membranes interconnected by polytetrafluoroethylene binder based on the dry process. The obtained membranes perform two-fold increase in ion conductivity at 30 °C of 2.55 × 10⁻³ S cm⁻¹ and the prolonged lithium deposition up to 1000 h compared to the pristine, which are attributed to synergistic effects in the inorganic/organic phase. Moreover, an integrated cathode/electrolytes design is proposed and exhibits excellent cycling performance with capacity retention of 98.8% after 200 cycles at 1 C. The corresponding pouch cells can light up LED after bending and recovery. This research provides new insights into the great potential of fabricating soft ceramic-based membranes in a low-cost and green way for highly-stable lithium-metal batteries.