Functionalized Metal-Organic Framework Composite Electrolyte Membrane for High-Performance Solid Li Batteries.

Metal-organic frameworks (MOFs)/polymer composite electrolytes have garnered worldwide attention because of their outstanding performance in energy-related applications. Here, a highly lithiated MOF (LZM) is designed as a filler into poly(ethylene oxide) (PEO). LZM is synthesized through a postsynthetic modified strategy to obtain preeminent single-ion conducting performance. The Lewis acidic sites in LZM interact with polymer segments and salt anions due to electrostatic interactions, which accelerate both the amorphization of PEO chains and Li transportation. Furthermore, the high content of Li and nanochannels in LZM frameworks facilitates the Li-ion transport in composite electrolytes, which is confirmed by the DFT result. The resulting composite electrolytes (P/LZM) achieve an ionic conductivity (6.86 × 10 S cm at 60 °C) higher than the control PEO membrane. The electrochemical stability window of P/LZM is up to 5.07 V, which is wider than that of the blank PEO. The Li|Li cells operate stably without degradation for 1876 h under 0.1 mA cm. The LiFePO (LFP)|Li cell based on P/LZM electrolytes maintains a reversible discharge capacity of 126.4 mAh g and commendable capacity retention of 90.8% over 450 cycles under 2 C. Collectively, all of the results suggest the P/LZM membranes are potentially stable solid-state electrolytes for solid-state Li batteries.